Set up the debug log so you can see if the proxy is forwarding the call to the spa122.
Info on setting up debug log at https://supportforums.cisco.com/docs/DOC-9862
After setting this up, make a call and see if the call shows up in the log file. If it doesn't, then you'll know that the proxy isn't forwarding the call to the unit.
You can also check if the unit is/isn't registered at the time of the call. Check the info tab of the web UI.
