Client authentication failed due to unknown client, no client authentication included, or unsupported authentication method.

Summary

After upgrading to 18.x we started to get the following error in GitLab Web IDE: Client authentication failed due to unknown client, no client authentication included, or unsupported authentication method.

Gitlab version: gitlab-ce.x86_64 18.5.1-ce.0.amazon2023 @gitlab_gitlab-ce

We upgraded to the following versions one by one and ran checks after each step: 17.10.3 to 17.11.7, 18.0.0, 18.2.0, 18.5.1

Steps to reproduce

We use http://localhost:80 to access GitLab in an internal server. After login, go to a project and try to edit a file with "Open in Web IDE"

A message will appear in the Web Browser: Unable to authorize GitLab Web IDE Access. For more information, see the developer console.

What is the current bug behavior?

It's not possible to use GitLab WEB Ide but "Edit single file" works properly.

What is the expected correct behavior?

I expect to use GitLab Web IDE.

Unable to authorize GitLab Web IDE Access. For more information, see the developer console.

Relevant logs and/or screenshots

I will attach them to the issue.

Possible fixes