It's not a matter of whom has the DID assigned to their set but rather whom has their OLI programmed with that DID #.
So check every OLI setting for every set.

Analog station issue, possibly related...check it's OLI too as well if there is something connected to that ports and if it has a hotline programmed on it.

The old trick for analog cordless working with a deskset was to revers the DN's since Answer DN does not work on an ATA.
You would have the cordless as the main DN and put an answer key for the cordless on the desk set , then program OLI on both the ATA and Digital DN's




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