I could not make the Panasonic KX-TGP500B04 behind the NAT. I have all the other phones in the same network no issues. Does any one have a working configuration for the FreeSWITCH and Panasonic KX-TGP500B04?

Is something to do with the source port. Panasonic KX-TGP500B04 always say "Registering" but never registered.