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How can I troubleshoot 500 errors with VPC link integration for Amazon API Gateway?

Last updated: 2022-11-01

I configured Amazon API Gateway with VPC Link integrations. When I call my API, I receive a configuration or internal error with an HTTP 500 status code. How do I resolve this issue?

Short description

AWS API gateway can fail to forward traffic to backend resources and return an HTTP 500 status code with VPC links if:

The VPC Link is in the Failed state, the endpoint service is deleted, or in the Rejected state.
The registered target for the target group is unhealthy or not in use.
Note: If no traffic is sent over the VPC link for 60 days, then it becomes INACTIVE . For more information, see Working with VPC links for HTTP APIs.
Security groups don't allow traffic on specific ports.
The network access control list (ACL) is blocking the traffic.
The target isn't listening on the target ports.
The domain name certificate isn't matching with the TLS enabled Network Load Balancer (NLB) or Application Load Balancer (ALB).

If Amazon CloudWatch logging is activated for your API, then an error message indicating the cause of the error appears in the execution logs.

Example HTTP 500 error messages in CloudWatch logs

Thu Aug 04 17:48:21 UTC 2022 : Execution failed due to configuration error: There was an internal error while executing your request
Thu Aug 04 17:48:21 UTC 2022 : Method completed with status: 500

-or-

Thu Aug 04 19:50:21 UTC 2022 : Execution failed due to configuration error: Host name 'domain.com.com' 
does not match the certificate subject provided by the peer (CN=myinstance.com)
Thu Aug 04 19:50:21 UTC 2022 : Method completed with status: 500

Resolution

Confirm the cause of the error

If you haven't done so already, turn on CloudWatch logging for your REST API. Make sure that you configure execution logging.

Tip: When configuring the logging settings, for Log level , choose INFO . Then, choose Log full requests/responses data .

Identify what's causing the errors by viewing the REST APIs execution logs in CloudWatch.

Check for the error message in the execution logs and follow these resolution steps

"Execution failed due to configuration error: There was an internal error while executing your request"

Verify that the VPC Link load balancer exists and hasn't been deleted.
Verify that the VPC Link is in the AVAILABLE state. If the VPC Link is in the FAILED state, then you must create a new VPC link and associate it with your API. Note: Be sure to deploy the API after modifying the integration request.
Verify that the VPC Link endpoint connection is in the AVAILABLE state.
If the VPC ID is referenced with a stage variable, then verify that the VPC Link ID is correct.
Verify that the VPC Link load balancer is listening on the HTTP/HTTPS port that the request is configured for. Check that the listeners are configured for the correct port. Check the network ACLs and make sure that they aren't blocking the request.
Verify that the target group is accepting the request. Check network ACLs to make sure that traffic is allowed inbound and outbound. Check the security groups to make sure that traffic is allowed inbound for the configured ports.
If the request returns a 500 error, the connection might receive TCP RST packets. Verify that the backend server is up and running. Verify that the backend target has a service running on the target port. Verify that the backend target is listening on the target port.

"Execution failed due to configuration error: Host name 'domain.com.com' does not match the certificate subject provided by the peer (CN=myinstance.com)"

Make sure that the endpoint domain name matches the certificate that's returned by the TLS enabled load balancer target.

"Execution failed due to configuration error: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target"

This error means that the API Gateway can't find the root CA. Even if insecureSkipVerification is set to true on the integrations TlsConfig property, API Gateway performs basic certificate validation including:

The certificates expiration date.
The hostname.
The presence of a root certificate authority.

"Execution failed due to configuration error: Cannot verify ECDH ServerKeyExchange signature"

This error means that because a key and the corresponding certificate don't match, the TLS handshake fails. To resolve this, verify the contents of the files used for your configured certificate authorities, certificates, and keys.

"Execution failed due to an internal error"

This error occurs because Amazon API Gateway couldn't connect to the load balancer over the VPC Link due to target resets on the load balancer. To resolve this, set the timeout on the target to be higher than the default timeout (350 seconds) on the load balancer.

"Execution failed due to configuration error: Not a valid protocol version: {Text of string}"

This error means that the integration responded with an invalid HTTP response which doesn't adhere to the HTTP specification. This might indicate that the Integrated backend is sending invalid data back to Amazon API Gateway.

To troubleshoot this error, do the following:

Reproduce the request made from Amazon API Gateway. Test the service endpoint used by Amazon API Gateway by creating a VPC endpoint that's linked to the service endpoint ID. You can also run packet captures to review the response that's returned from the integrated backend.
Change the load balancers protocol to TLS or TCP depending on the targets response to avoid duplicate encryption.
Make sure that insecureSkipVerification is set to true on the integrations TlsConfig property.

Related information

Understanding VPC Links in Amazon API Gateway private Integrations

Working with VPC links for HTTP APIs

Monitoring REST API execution with Amazon CloudWatch metrics

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Troubleshoot API Gateway certificate issues for custom domains using TLS

How can I troubleshoot certificate chain and self-signed certificate issues for Amazon API Gateway with custom domains and mutual TLS enabled?

Last updated: 2022-11-01

I am using mutual Transport Layer Security (TLS) authentication with Amazon API Gateway with a custom domain name. I am getting certificate chain or self-signed certificate errors. How can I troubleshoot this?

Short description

Before you begin, make sure that you have:

Set up a custom domain name for Amazon API Gateway.
Created the certificate chain and self-signed certificate.
Imported the certificate chain and self-signed certificate into AWS Certificate Manager (ACM).
Configured your truststore and upload it to an Amazon Simple Storage Service (Amazon S3).

Resolution

For a list of specific error messages when invoking your Amazon API Gateway API, run a curl command similar to the following:

$ curl -v https://mtls.example.info/test-apigw-mtls --key self-signed.key --cert self-signed.pem:"example"

Client errors

"curl: (58) could not load PEM client certificate, OpenSSL error error:02001002:system library:fopen:No such file or directory, (no key found, wrong pass phrase, or wrong file format?"

This error means that the PEM file has the wrong name, location, or file format. For example, the certificate file format stored locally is .crt , but the .pem file was used instead in the API request. To resolve this, make sure that the local client certificate has the correct format and name.

"curl: (6) Could not resolve host: mtls.example.info"

The client wasn't able to resolve the domain name. Make sure that the domain name and configuration are correct.

"url: (58) schannel: Failed to import cert file self-signed.pem, last error is 0x80092002"

This error means that there is an issue with the local client .pem file. Make sure that the .pem file includes the correct name and format.

"curl: (58) unable to set private key file: 'self-signed.key' type PEM"

This error means that there is an issue with the local client file. Make sure that the private key provided in the HTTP request is not missing and correct.

Server errors

"Access denied. Reason: self-signed certificate."

Verify that the self-signed client certificate in the API request isn't altered or corrupted.

The following must match exactly:

The modulus of the private key ( private.key ) used to sign the self-signed certificate within the truststore in Amazon S3 ( bundle.crt or bundle.pem ).
The modulus from the client's certificate passed in the API request ( client.crt ).

To compare the two modulus, run the following OpenSSL commands:

$ openssl rsa -noout -modulus -in private.key
$ openssl x509 -noout -modulus -in bundle.crt
$ openssl x509 -noout -modulus -in client.crt

Note: To produce a shorter hash value for easier comparison, you can use PIPE to send the output modulus into a cryptographic hash function. For example: openssl sha1 .

$ openssl [operation] -noout -modulus -in [data] | openssl sha1

Valid command output examples:

2143831a73a8bb28467860df18550c696c03fbcb
2143831a73a8bb28467860df18550c696c03fbcb
2143831a73a8bb28467860df18550c696c03fbcb

To confirm data integrity, verify that there wasn't any data modification at the content level by running the following diff command:

$ diff client.crt bundle.crt

Related information

Introducing mutual TLS authentication for Amazon API Gateway

How do I troubleshoot HTTP 403 Forbidden errors from an API Gateway custom domain name that requires mutual TLS?

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Create a private integration using an ALB for an API Gateway HTTP API

How to create a private integration using an internal Application Load Balancer for an Amazon API Gateway HTTP API?

Last updated: 2022-10-28

I want to create a private integration using an internal Application Load Balance for an Amazon API Gateway HTTP API. How can I do this?

Resolution

Follow these instructions to create the Amazon Virtual Private Cloud (Amazon VPC) link, HTTP API, private integration, and deploy the HTTP API.

Note: If you receive errors when running AWS Command Line Interface (AWS CLI) commands, make sure that you’re using the most recent AWS CLI version.

Create the VPC link

1. If you haven't already done so, follow the instructions to create an Application Load Balancer.

2. Open the API Gateway console, and in the navigation pane choose VPC links .

3. From VPC Links , choose Create .

(Optional) You can also create a VPC link by using the AWS CLI command create-vpc-link similar to the following:

aws apigatewayv2 create-vpc-link --name MyVpcLink \
    --subnet-ids subnet-aaaa subnet-bbbb \
    --security-group-ids sg1234 sg5678

4. From Choose a VPC link version , choose VPC link for HTTP APIs .

5. For Name , enter a name for your VPC link.

6. Choose the VPC dropdown list, choose a VPC for your Application Load Balancer to connect to.

7. For Subnets , choose your subnets to include in the VPC link.

8. For Security groups , choose the security groups for the VPC link, and then choose Create .

Create an HTTP API and route

1. Open the API Gateway console, and then choose Create API .

2. For HTTP API , choose Build .

3. For API name , enter a name, and then choose Next .

4. For Configure routes , choose Next .

5. For Configure stages , choose Next , and then choose Create .

6. In the navigation pane, choose Routes , and then choose Create .

7. For Method , choose ANY .

8. For path, enter /{proxy+} and choose Create .

Create a private integration and deploy the HTTP API

1. Open the API Gateway console, and then choose your HTTP API.

2. In the navigation pane, choose Integrations .

3. For Integrations , choose Manage integrations , and then choose Create .

4. For Attach this integration to a route, choose ANY /{proxy+} .

5. For Integration target , choose Private resource .

6. For Integration details , choose Select manually .

7. For Target service , choose ALB/NLB .

8. For Load balancer , choose your load balancer.

9. For Listener , choose HTTP 80 .

10. For VPC link , choose your VPC, and then choose Create .

11. (Skip this step if auto deploy is active) Choose Deploy to deploy your HTTP API.

12. For Invoke URL , copy the URL and paste it into a new browser window. For example, https://abcdef123.execute-api.us-east-1.amazonaws.com.

The HTTP API URL renders successfully in the browser window.

Related information

Amazon API Gateway HTTP API tutorials

How do I map the response status codes for API Gateway integrations in HTTP APIs?

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Pass a connectionId or custom token to VPC Link integration as a header for API Gateway WebSocket APIs

How can I pass a connectionId or custom token to VPC Link integration as a header for Amazon API Gateway WebSocket APIs?

Last updated: 2022-10-26

I want to pass a connectionId or custom token to VPC Link integration as a header for my Amazon API Gateway WebSocket API. How can I do this?

Short description

For WebSocket APIs, the connectionId is required to send a callback response from the backend. By default, WebSocket APIs don't pass the ConnectionId to VPC link integration.

Resolution

Using the Amazon API Gateway console and AWS CLI

Note: If you receive errors when running AWS Command Line Interface (AWS CLI) commands, make sure that you’re using the most recent AWS CLI version.

1. Follow the instructions to create a REST API VPC link and associate it with your Network Load Balancer.

2. Follow the instructions to set up a WebSocket API integration and create a VPC link private integration endpoint.

3. To retrieve the integration ID, run the AWS CLI command get-integrations similar to the following:

aws apigatewayv2 get-integrations --api-id <api-id>

4. Create and save a JSON file named integration.json in the following format:

{
    "ApiId": "<api-id>",
    "IntegrationId": "<integration id retrieved from previous step>",
    "RequestParameters": {
        "integration.request.header.ConnectionId": "context.connectionId", //passing context variable connectionId as ConnectionId header to backend
        "integration.request.header.<header-key>": "route.request.body.<parameter>", // passing a request body parameter as header to backend
        "integration.request.querystring.<querysting-key>": "'static value'" //passing static value as querystring to backend
    }
}

Note: Before proceeding to step 5 , remove the comments noted with the forward slashes " // ".

5. To update the integration, run the AWS CLI command update-integration similar to the following:

aws apigatewayv2 update-integration --cli-input-json file://integration.json

6. To apply these changes, follow the instructions to deploy the REST API.

Using AWS CloudFormation

If you manage Amazon API Gateway using CloudFormation, you can use the AWS::ApiGatewayV2::Integration resource to configure request parameters similar to the following:

Integration:
    Type: AWS::ApiGatewayV2::Integration
    Properties:
      ApiId: !Ref websocket
      ConnectionId: !Ref <VPC-Link-connection-id>
      ConnectionType: VPC_LINK
      IntegrationMethod: <HTTP method to backend >
      IntegrationType: <HTTP_PROXY/HTTP>
      IntegrationUri: "<endpoint-url>"
      RequestParameters:
        "integration.request.header.connectionId": "context.connectionId" #passing context variable 'connectionId' as ConnectionId header to backend
        "integration.request.header.<header-key>": "route.request.body.<parameter>"  #passing a request body parameter as header to backend
        "integration.request.querystring.<querystring-key>": "'static value'" #passing static value as querystring to backend

You can use data mapping to map data from a route request to the VPC link backend integration. For more information, see Map route request data to integration request parameters.

Related information

Setting up WebSocket API integrations

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Troubleshoot "internal server" error status code 500 for API Gateway enpoints with Lambda integration

How can I troubleshoot the "internal server" error with status code 500 for API Gateway endpoints that integrate with Lambda?

Last updated: 2022-10-19

I sent an HTTP request to my Amazon API Gateway API endpoint that integrates with AWS Lambda (for example, /lambda-resource GET). I received a status code 500 response with the following error: {"message": "Internal server error"}

How can I troubleshoot this error?

Short description

This error might be due to:

Lambda function permissions
Throttling issues
Incorrect or missing HTTP status code mapping
Unhandled errors

Resolution

Before you begin, follow the steps to turn on Amazon CloudWatch Logs for troubleshooting API Gateway errors.

Note: For Log level , choose INFO to generate execution logs for all requests.

Lambda function permissions

The error “Invalid permissions on Lambda function” occurs if API Gateway doesn't have permissions to invoke the Lambda function. To resolve this, see How do I resolve "Invalid permissions on Lambda function" errors from API Gateway REST APIs?

Note: If you used another service, such as AWS CloudFormation, to deploy your API Gateway resources, make sure that you have permissions to the AWS::Lambda::Permission resource.

Throttling issues

If the backend service is throttled due to a high number of requests, the API Gateway API might return an "Internal server error". You can activate an exponential backoff and retry mechanism and try the request again. If the issue persists, check your API Gateway quota limit. If you exceeded the service quota limit, you can request a quota increase.

You might also receive "Rate exceeded" and 429 "TooManyRequestsException" errors due to Lambda function throttling issues. For more information, see How do I troubleshoot Lambda function throttling with "Rate exceeded" and 429 "TooManyRequestsException" errors?

You can also request an increase for the Lambda function's concurrency limit so that the function doesn't get throttled. For instructions, see How do I request a concurrency limit increase for my Lambda function?

Incorrect or missing HTTP status code mapping

Incorrect or missing HTTP status code mapping can also result in 500 errors similar to the following:

"Execution failed due to configuration error: Output mapping refers to an invalid method response: 2xx/4xx/5xx".

To resolve this error, make sure that an API method response exists for the status code returned from the backend and is mapped correctly.

Unhandled errors

Unhandled errors in Lambda indicate that the function timeouts due to errors in the function code. To prevent this error, make sure that the Lambda function code is idempotent.

You can also use the debugging tool AWS X-Ray to get more details on how long different sections of your function’s code takes to complete.

For more information, see Error handling patterns in Amazon API Gateway and AWS Lambda.

Related information

How can I troubleshoot 5xx errors for API Gateway?

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Delete an Amazon VPC link for an Amazon Gateway REST API

How can I delete an Amazon VPC link for my Amazon Gateway REST API?

Last updated: 2022-10-04

I'm trying to delete my Amazon Virtual Private Cloud (Amazon VPC) link for my Amazon Gateway REST API and received the following error:

"Cannot delete VPC link referenced in format of [Method:Resource]."

How can I resolve this?

Short description

If a resource using the Amazon VPC link integration is deleted, then you can't delete the link.

Resolution

To delete the Amazon VPC link, follow these steps depending on whether the REST API was or was not deployed.

Deployed REST APIs

Switch the integration type from the Amazon VPC link to another type. For example, a mock integration, HTTP integration, or AWS integration type. After switching the integration type, redeploy the REST API to the same stage name that you previously deployed. Then, try deleting the Amazon VPC link again.

Undeployed REST APIs

Switch the integration type from the Amazon VPC link to another type. For example, a mock integration, HTTP integration, or AWS integration type. Then, try deleting the Amazon VPC link again.

Related information

Tutorial: Build a REST API with API Gateway private integration

How can I access an API Gateway private REST API in another AWS account using an interface VPC endpoint?

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Welcome to Knowledge Base!

KB at your finger tips

How can I troubleshoot 500 errors with VPC link integration for Amazon API Gateway?

Short description

Resolution

Confirm the cause of the error

Check for the error message in the execution logs and follow these resolution steps

Related information

How can I troubleshoot certificate chain and self-signed certificate issues for Amazon API Gateway with custom domains and mutual TLS enabled?

Short description

Resolution

Client errors

Server errors

Related information

How to create a private integration using an internal Application Load Balancer for an Amazon API Gateway HTTP API?

Resolution

Create the VPC link

Create an HTTP API and route

Create a private integration and deploy the HTTP API

Related information

How can I pass a connectionId or custom token to VPC Link integration as a header for Amazon API Gateway WebSocket APIs?

Short description

Resolution

Using the Amazon API Gateway console and AWS CLI

Using AWS CloudFormation

Related information

How can I troubleshoot the "internal server" error with status code 500 for API Gateway endpoints that integrate with Lambda?

Short description

Resolution

Lambda function permissions

Throttling issues

Incorrect or missing HTTP status code mapping

Unhandled errors

Related information

How can I delete an Amazon VPC link for my Amazon Gateway REST API?

Short description

Resolution

Deployed REST APIs

Undeployed REST APIs

Related information