Wrong webfinger incorrect report on docker image

[surli]

Describe the bug
I just performed a trial of Social app on a Nextcloud docker installation (nextcloud:stable), and I got a warning about .well-known/webfinger being not properly set-up.
However if I perform a request manually on it, it works perfectly.

To Reproduce
Steps to reproduce the behavior:

1. Launch Nextcloud:stable docker image (embedded database but I don't think it would change anything)
2. Install Social app
3. Go on the social app

Expected behavior
No warning related to WebFinger since I got the right answer when requesting it manually (e.g. http://localhost:8080/.well-known/webfinger?resource=acct:surli@localhost gives me the right JSON answer)

Screenshots