D124 Access to user (name here) denied

[jediblue]

Facts:

Domain and all PO's are setup client server

This error occurs from local po and other po's on domain
from user's trying to access the same user. (user's A, B, C, D, & E all trying to access user X, some are local some
are across the MTA

All tids found have been tried; checking to make sure rights were assigned, resetting client options, removing users from his proxy list and putting them back in, putting rights back.

Error still occurs.

Any ideas folks?