An error 'There is no such database user' is shown on attempt to change database user password:
There is no such database user, user_id=XXXX
Such error occurs if database is used by APS application installed in subscription, the password for such databases cannot be changed. The software issue with ID APS-29487 has been fixed in OA 6.0 update 7.
Please schedule installation of OA 6.0 update 7 with your TAM/PTA.