I have spent the last 3 days trying to get my home phone to work after switching to Phonepower. I kept getting "registration failed: No response from server" errors on my OBi100. After a miserable tech support chat with Phonepower last night, probably 100 resets and re-provisions of my OBi and DMZing my OBi, I was getting nowhere and was about ready to give up. I am pretty tech knowledgeable but I will admit that, when it comes to VOIP set-up, My skills are severely lacking.
I think I have found the source of my woes but would like someone much more knowledgeable on this than me to confirm that I am doing this correctly.
Like I said, My OBi would never provision correctly with Phonepower but I found a setting that seems to make my OBi work correctly. That setting is: Voice Services -> SP1 Service -> X_UserAgentPort. This setting was originally remaining set at it's default of 5060. After changing this setting to 12060, My OBi is now Registering and working correctly. This is the only setting I changed. I know this may be a stupid question but is this correct? I will say that, at least in my case, something seems to be off with Phonepower's auto-provisioning and this doesn't instill the greatest level of confidence in me about it's service.
Obihai had problems in their provisioning script. I had the same issue and opened cases with PhonePower and Obihai. Eventually Obihai determined the problem was in their provisioning script.
I also made the mistake of not performing a factory reset on my Obi202 device. Because I am a "technical" person I did not think this would be necessary. Unfortunately, as you have discovered, deleting a configuration is not a clean operation. Settings still remain hidden and cached.
After Obihai fixed the problem with their provisioning script, I had to perform a factory reset on the Obi202 and re-add the device to the ObiTalk portal. Only then would re-syncing the device through PhonePower work and allow the registration to succeed.