I had the same problem. Made sure annunciator is in MRGL and service parameter is set to use ANN for ring back. However that did not work. The fix for me was to change the device pool network locale to none or to the one I installed. I'm in Australia...

I had the same problem. Made sure annunciator is in MRGL and service parameter is set to use ANN for ring back. However that did not work. The fix for me was to change the device pool network locale to none or to the one I installed. I'm in Australia...