I have project setup based on the AspNetCoreWebApp template from aws-lambda-dotnet.
The lambda entry point is setup the same as the template.
I can see an unsecured page fine, but when attempting to go to a secured page, I get a 502 Status Code response from the load balancer.
Based on aws troubleshooting:
The target response is malformed or contains HTTP headers that are not valid.
The lambda function redirects work fine fine with API Gateway in front of it.
Don't forget to read the Readme:
Change the base class to Amazon.Lambda.AspNetCoreServer.ApplicationLoadBalancerFunction when using an Application Load Balancer.
Although the Lambda function seems to work using the APIGatewayProxyFunction base class, the headers for Content-Type will come back as [null] during a redirect which the ALB does not appear to support. Change the base class of LambdaEntryPoint to ApplicationLoadBalancerFunction and the redirects will work correctly.