Just upgraded to 3cx version 15.5 and in the process also moved my DID line from an analog line to a VoIP line with Vitelity. I've created the DID trunk and have outbound calls working just fine through my DID number, but cannot get incoming calls to work at all. Inbound calls just get a busy signal and an email generated from Vitelity saying VoIP services call failed. In trying to lookup this issue I noticed another user had the same issue, but no resolution. I have tried to delete the SIP Trunk and re-add it, but nothing changed. I'm using a Cisco router and I've created an IP NAT rule to open all ports to troubleshoot issue and the firewall check is showing green. Incoming calls are not showing up in the event log (or call log) but outgoing calls are showing up in the call log. Any recommendations?