Ran OMVSTRACE which revealed a RC 8 8 84 being received for a r_datalib RACF Callable Service.
8 8 84 means the keyring is not found.
The keyring label specified via LABLRING in CA Top Secret must match the keyring label specification in MQ.
The keyring label must be an exact match and is case sensitive.
After making the correction, they were able to issue the MQ REFRESH command.