Hi, I have our system setup to use a number of VOIP providers. Amongst which - i have setup an option for incomming VOIP calls to be directed / routed to the 3CX server. I'm finding a problem in that I can have this setup, and it works fine - but then after a few minutes, it will not receive any calls. Anyone trying to call through just gets silence on there phone. According to both 3CX, and the end VOIP provider, I am still registered, but the calls won't come through. If I restart the 3CX server, the calls will come back through again for a period of time. I am behind a NAT firewall to have access to the internet. I have opened up port 5060 from the outside to go to my 3CX server. There are no restrictions on outbound packets. Can anyone suggest what might be causing this? Thanks & Regards Adam.