Sounds like incoming call route problem to me.
The SIP provider sends you the request but teh IPO doesn't know what to do with it.
Do a Monitor trace with all options disabled but SIP tab (only left hand side checkmarks) then call in and see what you get.
If you take out all private data then post it here and we can look but so far I think incoming call routing is the problem.
Joe W.
FHandw, ACSS (SME)
"This is the end of the world, make sure to buy your T-shirt before it is too late"
Original expression of my daughter