Load balancer returns HTTP 502 when targeting lambda

Hello aws community,

I have an issue with a lambda in which I ended up returning the hardcoded response like shown below ... response = { "statusCode": 200, "statusDescription": "200 OK", "isBase64Encoded": false, "headers": { "Content-Type": "text/html" }, "body": "<p>Test string returned from Lambda</p>" } return response;

I have played around with headers and content-types ... Nothing seems to resolve the issue.

When checking the ELB logs I see ... https 2023-01-24T20:04:03.214570Z app//******* xxx.xxx.xxx.xxx:xxxxx - 0.008 0.538 0.000 502 - 1629 277 "GET https://*************************************:443/************* HTTP/1.1" "PostmanRuntime/7.29.2" ECDHE-RSA-AES128-GCM-SHA256 TLSv1.2 arn:aws:elasticloadbalancing:**************************************** "Root=" "***********************************" "arn:aws:acm::certificate/***************************" 0 2023-01-24T20:04:02.667000Z "forward" "-" "LambdaInvalidResponse" "-" "-" "-" "-"

Does anyone have any ideas on how I could further troubleshoot this issue? Is there maybe a way to verify what the load balancer is receiving as a response from the lambda? I have tried logging what the lambda is returning. To me it seems correct and in line with what I find in forums that address similar topic.

Greetings,

Hamid K.