Hello, A time ago I had the same issue, but this time it seems to be not so easy repairable. Code: Registration at * has failed. Destination (sip:*) is not reachable, DNS error resolving FQDN, or service is not available. Code: Registration failed for: 10004@*; Cause: 408 Request Timeout; internal Code: Next attempt to register 10004@* is scheduled in 600 seconds What I tried myself: Firewall Issues: Not the point. I ran a Firewall-check and it passes all OK. Also, the same SIP-Account registers on a handset in the same network just fine. Contact Tech Support: I am afraid I have no tech-support subscription. Also, sometimes I ain't be able to call someone. It keeps reconnecting forever. Code: Call to *@(Ln.10001@*) has failed. [ V4 0.0.0.0:0 UNKNOWN_TRANSPORT target domain=unspecified mFlowKey=0 ] replied: 408 Request Timeout; internal What could cause this issue? Remember, all these lines connect on my handset itself just fine! Thanks for the support / thoughts.