Phones ring to wrong ext

Weird issue here.

Now upfront we have an old PBX hasnt been updated in yeas and using yealik T42.

This does not happen with all extensions

If I dial by ext internall or DID externally the ext will ring a couple of times.

then it will ring another ext a couple of times, if no pickup by the second ext the VM will pickup for the first ext and VM can be left to originally called ext or DID.

IE I dial ext 400, it will ring the physical phone 2 times, then seems to forward to ext 401 ring a couple of times if ot picked up then will retunr to ext 400 vm.

I cant find anything that forwards ext 400 to 401 at all.

Im a bit baffled and was hoping some one might have an idea.

Again this setup is really old

The PBX vm has been rebooted once or twice just to see if it helps, still happens

check your SCFW (second level call forwarding), “X” it if you do NOT want the initial call to go to a 2nd user before reaching initial callee’s voice mail.

Sounds like Follow Me is enabled for EXT:400
https://sangomakb.atlassian.net/wiki/spaces/PG/pages/23396734