Hello, we are using the latest 3CX V15 Version. We are facing since the latest Update (3CX Phone System v15 SP5, Build 15.0.62928.5) an issue with the 3CX iPhone & Android Clients. We cant make any Calls from an External IP (4G / 3G) Call. If i test it from the Corperate Network it works fine. Anyone an Idea?