I have searched the forum for this already but what I have found so far hasn't been the solution to my problem. I get the following error, like a few others here have gotten: Call or Registration to OutsideNumber@(Ln.10000@Patton ISDN T1) has failed. PBXGateway replied: 503 Service Unavailable; from IPBXGateway:5060 Currently running 3CX v15 SP1 while using a Patton SN4970 Gateway with T1 service provided by Windstream. Tested the line going to the outside world and it tests fine. On the status page of the Patton gateway, it lists that the E1/T1 link is down. But I'm grasping at straws as to what the cause could be. Any advice would be much appreciated.