I was on v14 until today. We didn't seem to be having issues on v14 - atleast nobody mentioned anything to me. When I ran the firewall checker on v15 - some RTP ports failed as "full cone test fail" and others "not reachable". The strange part about this is that the ports change on every test. This time, ports 9002, 9003, 9004 might fail and the next 9025,9026,9027,9030,9040, etc. Also, voice in and out is working fine on the Flowroute trunk - as well as remote extensions. SIP service is disabled on the Mikrotik, RTP Ports 9000-9255 on UDP forwarded. Also outbound NAT is setup so all traffic from PBX is seen as the Static Public IP setup in 3cx. Any one with experience with Mikrotik know what to check.