redirect uri mismatch

Description

I have multiple reverse proxies (different fqdn) in front of the gitlab-ce. Is it possible for the google oauth module to recognize different base url fqdn? On the google console side, I can configure multiple fqdns, but the gitlab google oauth module throws:

Could not authenticate you from GoogleOauth2 because "Redirect uri mismatch : { "error": "redirect uri mismatch"}".

Only the reverse proxy whose fqdn matches "external_url" in /etc/gitlab/gitlab.rb works.

Proposal

Google oauth module should allow defining multiple base fqdn, or can external_url take multiple values?

Links / references