wp-admin redirect

Hello,

I’ve just setup wordpress with docker installation.

Apache2 serves as a reverse proxy (ssl termination).

Website works fine but (URL: https://www.mydomain.com/blog), after logged in, wp-admin always redirects to https://www.mydomain.com/wp-admin/ and removes the “/blog/” part in URL.
I’ve tested with plugins/themes disabled or emptied cache as same problem occurs.

Any idea what could cause this problem ?

Thank you in advance.