Access server which is running internally in a job

Dear gitlab community,
I have a job in a stage which needs to test the application. I would be running two threads. Application thread and the Test thread. Problem is the test thread is not able to connect to the application server. When testing locally, I use localhost:3030 to connect to the application server. In gitlab CI, can I get some help to achieve the same

  • What version are you on? Are you using self-managed or

    • GitLab Enterprise Edition 16.8.0-pre
  • I have tried changing the localhost:3030 to