You moved a sight to a new phone system with a DID range of 777-777-7700 thru 7800 instead of porting your old DIDs numbers to the new system?
(You can ignore the mention of 777-777-777, it's not a new DID range or anything, I'll explain it at the end)
The numbers actually
have been ported over - six lines that were originally part of the Mitel system at our main location are now part of the cloud system, those 6 phones are physically located at an offsite, and have retained the same numbers that they originally had when on the Mitel system. Once they did the cutover, we can call the newly ported/migrated phones from any external line (cell phones, external land lines, etc), we just can't call them from the old Mitel system that they used to be part of at the main site, where the other 134 phones are still at.
When I attempt to call one of the ported numbers from the Mitel system, they are still in the Mitel routing table (as 666-666-666_) so it goes straight to the old voicemail for that line. That all makes sense because it still exists in the routing table, and the extension & voicemail are still there. So the question is what's the best way to go about this because I'm only guessing. My first guess was to delete any trace of one of the lines and make a phantom extension that is forwarded to the DID. Here are the phantom settings which are identical to ones that we've been using for things like an after hours answering service (at the end of the day the main reception phone forwards all of their calls to it):
Phantom extension 6661Associated Extensions:
> Attendant: NONE (also tried with front desk extension here)
> Message Center: (front desk extension)
> Alternate message source: NONE
> Transfer Recall Destination: 6661
> Voice Mail: NONE
> Outgoing Extension: NONE (also tried with 92001 here)
> Agent Help: NONE
> Agent Help User-Keyed ext: NONE
> Emergency Extension: 92001 (that is a CO Trunk Group, description is PRI)
> Associated User Extension: NONE
Forward Information:
> Forward Destination Extension: 92001
> Forward Username: Outside
> Forward Description: PRI
> Forward Outside Number: 1-666-666-6661 (also tried it without 1 for long distance)
> Forward Extension: 355
> Forward Type: 1
> Forward Public Network: Yes
But when I dial the phantom extension (6661), it goes straight to the front desk line. Like I mentioned, we have a bunch of phantom extensions configured exactly like this that successfully go out to the external number set in "Forward Outside Number". The above (666-666-6661) was one that I removed from Routing Table, Extension, and Voicemail, so theoretically Mitel would have no trace of it. Also since you mentioned System Forwarding, it's worth noting that this phantom extension (nor any of the working ones) have anything under Forwarding Paths.
With one that is still in Routing Table, Extension, Voicemail, I tried setting the Forward Information of the extension itself (not a phantom extension) to point to the ported number (i.e. 666-666-6665), but calling that is when it just rings indefinitely to seemingly nowhere, no phone is actually ringing on the other end as far as I can tell.
The 777-777-7777 number isn't a range or anything, just a fake/throwaway number I added to give more troubleshooting clues. Of the 6 lines at our offsite which are now in the cloud portal, if you browse these extensions, one of the lines has a secondary number. I mentioned that it was 777-.... as a throwaway, but it's actually just something random that doesn't seem to follow any numbering pattern in line with our old phone system, local area codes, etc (something random like 684-508-8435). I only included this info because it seemed interesting that, of the two DID numbers listed for that phone in question: one is 666-666-6665 (ported legacy Mitel DID) and 684-508-8435 (only showed up once line was added to cloud system), I can't call the legacy DID number that has been around forever, but I
can call the new cloud number.