Credits to Val, thank you for your help.
The attached PDF will help you set up your SPA2102 device from scratch. It is a known working configuration so if you are having troubles with your SPA2102 reset back to defaults and follow this guide.
Edit:
1) Navigate to Voice-->SIP-->SIP Timer Values (sec)
Reg Retry Intvl should be 120 seconds
https://support.freephoneline.ca/hc/en- ... redentials
2) Also, Navigate to the SIP tab-->NAT Support Parameters, and make sure that the following settings are enabled:
a)Handle VIA received-->yes
b)Handle VIA rport-->yes
c)Substitute VIA Addr-->yes