Hi,
I'm having the same problem here.
I switched from a WISP connection (with IP static address) to a FTTC connection at radio side.
I can't connect anymore the radio, same error at control side: connection status faulty, connected transfering, RTP/UDP audio status: Stalled
At radio side seems OK (OK, connected/transferring).
The FTTC ISP declares that all ports are reachable, I have a dynamic public IP address, the remoterig ddns works well.
The web interface of radio side is working on port 81 and is reachable with no problem (of course I forwarded port 81 to radio control).
I tried to change ports, from 13000-13002 to 13003-13005 and then 65532-65534 but nothing changed (of course I changed and I opened the port on radio FTTC router).
Any idea? by my side no...
The only possible solution that pops out in my mind is to setup a PPTP Router to Router secure tunnel (something like this
https://mikrotik.com/testdocs/ros/3.0/vpn/pptp.php ) in order to use same radio side ip class at control side
thanks in advance
73 Andrea IK1MVX