I have upgraded to version 11 and have Grandstream 2100 phones with frimware 18.104.22.168. In ver 10 the phones had to blfs as SPO and SP1. Calls could be parked by answering call then press transfer then a park button. Now when you press the transfer button a message appears on screen to dial ext or select button. The call will not park when the park blf button is selected, it can be transfered by dialing an ext. I have given the users the rights to park and un park calls. What am I missing to use this function? The phones were provisioned with 3cx.