Calling AWS from Azure APIM not giving response few times - Intermittent issue

Question

There is an issue while calling the REST API and the application resides in AWS. This call is made from Azure APIM and kind of PROXY call. It means , in the Java code there is an another URL visible to the user and while calling in turn call the REST API of the application which is in AWS.

There is an intermittent issue of not getting response few times. Most of the times , there is 200 response but few times 500 INTERNAL SERVER error is returned.

Mostly , this seems there is a network issue.

As a workaround , retry mechanism is added to call the API 3 times. Still , few failures are noticed in production.

1. As of today, it's an unknown that where exactly the request from Azure (APIM) -> AWS is rejected/lost. 2.The request is not reaching HAPROXY in AWS side

requesting experts to help with your suggestions for the further investigation steps.