App does not establish call or shows own video in MIUI 11

I have a Pocophone F1 running the latest MIUI 11. When I establish a call, the app hangs on ‘calling’ and after 45 seconds it hangs up with the message “No reaction please try again”. It does not show the own video (even after I gave all the permissions regarding mic/camera…) so it must be something app related and not with the Nextcloud instance (I also tested it on 3 different instances and also with another smartphone which does succeed in establishing a call).

I tested apps 7.0.8 through 8.0.9, all with the same results. How can I solve this, or is this a bug?

Nevermind, I must have done something wrong or so, today I tested it again and it does work flawlessly.
My mistake … :slight_smile: