Hi,
You may want to make sure your firewalls are off and also open up ports for your ATA via your router's web interface might help. After accessing the router's menu, you should see admin settings, then forwarding and set these parameters for the sip port you are using for your ATA and these additional ports as well:
Configure these areas with the port numbers and ranges (ie. 5060-5061), IP Addresses of your ATA, and by placing checks in the check boxes; the Port, the Protocol (udp/tcp), the IP Address , and Enable such as:
ports 5060-5061, check tcp and udp boxes, ATA IP, Address check this box
(and do the same for these port ranges for your ATA unit 53-63, 69-69, 10,000-20,000 )
Also if you need more info, you can visit my site which briefly discusses how to setup a PAP2T/PAP2 at
Voipme2u Voip Services
stegels