I've just received a Panasonic KX-TGP500 to replace the dying Siemens IP phone I use with 2talk, and I have configued it with the usual settings but just can't seem to get it to work.
The phone will register, but I can't make any calls in or out. Trying to dial out I just get a tone similar to the NZ busy indication (but no message to indicate what the problem is).
With an incoming call, the phone rings, but as soon as it's answered, it just drops the call to both parties.
I don't have any issues like this with either the Siemens phone I've been using until now, or the CSIPSimple soft phone on my Android.