I recently upgraded my client from 5 to the latest build of 6, and for whatever reason I am no longer able to connect to my 3CX server. I keep receiving "authentication failed" and I've ensured my login credentials are correct. I've also tried connecting with and without STUN, and deleting/recreating extensions with no luck. Finally I tried with a tunnel connection but I've never been able to get that to connect (still am unsure as to why). All my earlier version clients connect with no problem. I was curious if anyone else has experienced connection issues after upgrading, and if so how they resolved it. Thanks!