Problem

On submit/save actions, Jenkins improperly redirects to http on port 443 causing the error message to be returned The plain HTTP request was sent to HTTPS port

High Level Architecture

• In AWS, an ACM is attached to the ALB
• A listener rule in the ALB is configured to redirect http to https
• By default redirect 8080 to 443
• The Jenkins Server is behind nginx and listens to port 8080

Steps to Reproduce the Issue

1. In your browser, go to http://myjenkinsexample.com:8080
2. http://myjenkinsexample.com:8080 is redirected to https://myjenkinsexample.com
3. Click Login and submit login credentials
4. ERROR

• Browser redirected to http://myjenkinsexample.com:443
• An error page is displayed with the following error

400 Bad Request, The plain HTTP request was sent to HTTPS port

Question

Where do I fix the configuration so that on "submit" requests, it redirects to https on 443?