rport IP in SDP

[dig1234]

Thanks for your reply.

account.1.nat.rport = 1 is worse. rport = 2 works most of the time. What I noticed is that if a user receives a call very fast after hanging up the previous one the audio does not connect. I can see in 3cx logs that the SDP is pointing to phone's local IP for those calls. If I turn on STUN it messes up the ports. Is there a way to tell the phone the NAT IP without port discovery?