Lambda non-proxy integration errors out with "IntegrationError: Execution failed due to configuration error: Unable to transform request"

I am trying to set up the simplest possible lambda non-proxy integrated endpoint and I am getting a 500 Gateway response from Api-Gateway and the logs show me the above API_CONFIGURATION_ERROR “Unable to transform request”. I had path parameters in my path and was trying to do this with async: True but have since removed all that and am just trying to get a bare-bones endpoint up but am still failing.

The functions section of my serverless.yml looks like this:

    handler: wsgi_handler.handler
    timeout: 30
      - http:
          method: any
          path: '/{proxy+}'
          authorizer: aws_iam
          cors: true
    name: ${self:service}-${env:ENV_CODE}-bar
    handler: wsgi_handler.handler
      - http:
          method: post
          path: /bar/abc
          integration: lambda
          authorizer: aws_iam
            passThrough: WHEN_NO_MATCH

The API Gateway logs show me the above Integration Error but I see nothing in the lambda logs. I’m using the serverless-wsgi plugin and have manually put in logging statements at the first line of the handler function there but the lambda seems to not get triggered at all as there are no logs. I do want to point out I am using a custom version of the plugin and expect some error there but the request doesn’t seem to be getting that far at all.

My suspicion is that somehow the default request templates are failing to transform the request and I can’t understand why. I’m sending a normal post request with no body and tried both with and without a Content-Type: “application/json” header but have had no success.

I’ve tested this with the serverless framework versions 2.34.0 and 2.35.0.

Really appreciate any thoughts on what might be causing this or any advice on how to debug this further.