Jitsi Meet: chrome client remains "connecting"

Sorry guys, not sure if this is the right place for trouble shooting… :wink:
After two weeks and about 100 successful sessions, I’ve gotten the first support case now:
A user called, her chrome remains “waiting for the connection” when moderating. When I open a meeting with the same name, everything works as expected.
Any idea what’s going wrong? TBH, I wasn’t getting a clue out of the logs.
As usual, any help highly appreciated.

Logs are saved, but I wasn’t able to attach them here.
But jicofo keeps repeating
Jicofo 2020-05-04 11:20:05.033 INFO: [74] org.jitsi.jicofo.xmpp.FocusComponent.handleConferenceIq().401 Focus request for room: 2b@conference.meet.here.local