Glad that Reliable Disconnect solved your problem.

That may have been it, lines locking up the VM ports until they can't answer any more calls.

Or, you could have a dead line in the hunt sequence, and anytime an incoming call hits that trunk, it's ring-no-answer.

The phone company could also have screwed up the hunting, and have it hunting into the twilight zone.

So, you should call each of your lines individually, and make sure that they answer.

Then you should test your hunt group, by picking up a specific line, and dialing that line's own number, to confirm that it hunts to the next line in sequence. When you hit the last line in the group, dialing its own number should return a busy signal.