Really Really Odd One...

One server...
Works great.
4 outbound handsets all set up fine...
One outside location when they try to ring anyother extension... They get through and there is voice both ways...
If that same extension then hangs up and rings a real number they cannot hear anything...
So they can hear with other extensions on the same server but not when ringing out of the server to a landline.

Phone is remote nat phone Snom3
server asterisk 1.4.21

If you do an RTP debug.... only the phones ip appears not the phone and a remote ip...

well I said it was odd...