NEC Phone System not accepting calls since using UXG Pro

[AB_IT]

Hey All,

Hoping someone here might know what's going on. Basically we have a Leased Line coming into one of our buildings and a SIP/VOIP phone system. The leased line has an external IP dedicated to this phone system which is mapped to our Phone Network VLAN (Confirm this by putting a device on VLAN and asking Google What's my IP). We have two other VLANS that point to a different external IP.

Since doing this however the phone system will work and then if no one has dialed out externally for some time the phone system won't see an incoming call from an external number. Using Wireshark we can't even see the traffic on the network almost as if the UXG Pro is somehow preventing the incoming call. If you dial externally again from the phone system once it's stopped working and then straight after dial into the building again it starts working for a while?

Thinking it's the firewall I've tried making two entries in the firewall to allow all port/traffic from the two external IP's which deliver the incoming call to the phone network but to no avail. I've also removed the phone network from the 'Suspicious Network Activity' list and added 'SIP' option to Contrack Modules to see if that would do anything but it's still having problems. The Unifi Controller isn't showing me anything in the logs that I can see.

If anyone can help I'd really appreciate it as we're really stuck with this one!

[FN-GM]

I would look to see if SIP ALG is enabled. If so disable it. Causes all sorts of funky stuff with SIP.