OK, so we eliminated the SP2 configuration as a possible cause, and you can add it back. The next step would be to delete the SP3 configuration, and add it back again, as I explained earlier, using the OBiTALK dashboard's custom settings for Callcentric.
If it still fails after that, then I'd go back to my first guess, that you have some sort of issue with your OBi not being able to register to the Callcentric server.