Magento does not recognize the own backend URL and displays 404

[ahmadbassi378e]

I have a Magento2 store divided into three docker containers: Magento2 Maria DB Nginx

The Nginx receives all queries and forwards them to the Magento2 container. This one processes the incoming request. But when I try to call www.mydomain.de/backend-url, Magento does not recognize that it is the backend URL and displays a 404. I have already cleared the cache, I have also checked in env.php what is stored, I have also checked the unsecure and secure URL in the database and also checked in the database the redirects. Also, the backend URL was already changed via the Magento CLI and led to no result. When I ask via client which URL is responsible for the backend, it shows me it correctly, but when I enter it in the browser, a 404 is displayed. Can anyone help?

[rimshadevr27ac]

1. Check Nginx configuration for Magento URLs.
2. Verify backend URL settings in Magento's env.php.
3. Ensure proper URL rewriting in Nginx or .htaccess.
4. Confirm correct file/folder permissions for Magento.
5. Check Nginx FastCGI or proxy cache settings.
6. Verify Docker container networking.
7. Examine error logs (Nginx, Magento, PHP).
8. Clear the Nginx cache if applicable.
9. Check browser cache/cookies or use incognito mode.
10. Temporarily disable third-party modules to check for conflicts.

Systematically reviewing these areas should help resolve the issue. If needed, seek help from Magento forums or support.