username validation

[amanu-nur]

Hi everyone, I am having a problem where the username format (area@username) fails if you use another user, what can I do and how to handle it?
Mikrotik Log: <0b9b>: user dukuh@darti authentication failed attributes: { 'Service-Type': 'Framed-User', 'User-Name': 'dukuh@darti', 'Vendor-Specific': { 'Mikrotik-Realm': 'darti' }, 'Acct-Session-Id': '81700b74', 'NAS-Identifier': 'MikroTik' }