Revert password hash function to the supported encryption type
If you reverted from ONTAP 9.1 or ONTAP 9.0 to ONTAP 8.3.x, SHA-2 account users can no longer be authenticated with their passwords. Passwords must be reset to use the MDS encryption type.
Set a temporary password for each SHA-2 user account that you identified prior to reverting:
security login password -username user_name -vserver vserver_name
Communicate the temporary password to the affected users and have them log in through a console or SSH session to change their passwords as prompted by the system.