I have a KX-TA824 connected to a KX_TV50 vps that has 4 ports in it. I have port 1234 connected to jacks 7,8,15,16 respectfully on the PBX. I have the PBX set for APT and the VPS set for 824 and APT. when I try quick setup it says it cannot retrieve extension and name details. also when i try to connect to VM it says the port is "busy". If I set it up for inband everything seems to work fine but I really want the features of apt. Any idea whey this is not working?