Wrong time and no connection to users

Talk is using the utc time not the local time. How could i change this. It is a little bit annoing to have a 2 hour shift in it.

But more important i have this problem:

I could start a videocall with any guest in a second but if i try to call a other user the connection is never established. It doesnt matter where the other user is located, if this person is switching to a guest-link it is working but as user not.