We upgraded our Modular ICS to 7.1 last weekend. Since then, the second channel on the mailbox ports switches by itself from "STK1" to unassigned and back. When it is unassigned, we can't send calls to mail boxes.
Now for the really weird part. Our T7316e phones seem to find a working channel, our other phones (T7316, M7324, M7310, and M7208) can't. It is StartTalk 2.0.
Any ideas?