Hi, I have a very strange problem with my 3CX server installation. Calls from external clients of my 3CX connected over Tunnel using 3CX client are disconnected after about 40 seconds. But when someone from internal network (where the 3CX server is installed) calls a previously mentioned external client, there is no call termination. What works without a problem: 1. Calls between clients inside my home network work without any problem. OK. 2. Calls from clients inside my home network to external clients over VOIP provider do not have any problem. OK. 3. Calls from clients inside my home network to external clients that are connected to my 3CX do not have any problem. OK. Does anybody have any idea what that would be? My 3CX server is: 3CX Phone System Version5.1.4510.0 The problem occurred a few weeks ago when I upgraded and reinstalled the 3CX server. I had to reinstall my complete server including Windows Server System. I backed up the old installation then uninstalled the old installation and installed a new fresh installation. After the new installation was made I restored the old backup. But I had a problem here, because History didn’t want to restore. All the history was corrupted and didn’t want to log calls. This is why I made another backup without a history and reinstall everything. After that my history log worked. But I think this is nothing with my problem I described earlier.