This problem could be on AT&Ts end, or some communication provider in the middle. I have a similar configuration set up for my work extension (not related to Gr

This problem could be on AT&Ts end, or some communication provider in the middle. I have a similar configuration set up for my work extension (not related to Grandcentral/GV). The GC/GV system basically works as a man in the middle, and it relies on ISDN or SS7 (I believe) signalling to indicate that the call wasn't completed in a message right before VM picks up. Incoming callers can hear the first second of my personal VM before my work VM takes back over. If the connection signalling is being stripped by some intermediate link or network misconfiguration GV can probably fix it, or trouble ticket their providers to do so. When you submit your info, make sure you tell them: 1) The cell # affected, including if it's a "blue" (refers to Pre-AT&T, pre-Cingular, AT&T Wireless) number or "orange" (Cingular) number if you know. 2) The local area of that # 3) If the number was ported and from where (eg. from Sprint or T-Mobile) 4) Where you are (in course terms physically, and whatever detail you can provide network-wise) when the failures occur 5) Whether the transfer to VM occurred because your phone was busy (you were calling out at that moment), unavailable (off, underground), directed to VM (you pressed END while it was ringing), or it rang the 30 seconds away and then timed out. This should be enough to give them a fighting chance at a test case or correlating it to another ticket (e.g. Los Angeles AT&T customers ported from Sprint) and getting it fixed.