I have tried:

zac retr, which fails as it says there is no zone to which this agent
is connected

zac reg, which fails because of error 34 Invalid device authentication

zac rereg GUID, which fails because of missing zone (as zac retr)

zac unr, which fails because of the same error.

zac ci shows the correct certificates

almost everything is working except registration refresh and location

What to do in this situation?

ZCM 11.2 with latest update (Monthly update 1)
W. Prindl