ORA-40369
Only NO AUTHENTICATION user can be marked as dictionary protected.
Cause
An attempt was made to add dictionary protection to a user with AUTHENTICATION_TYPE set to a value other than NONE. Query SELECT USERNAME,AUTHENTICATION_TYPE FROM DBA_USERS to confirm that the user has an AUTHENTICATION_TYPE other than NONE. Only database users with AUTHENTICATION_TYPE=NONE can be configured with dictionary protection.
Action
Find the correct user with AUTHENTICATION_TYPE=NONE by running SELECT USERNAME,AUTHENTICATION_TYPE FROM DBA_USERS or change the user to have no authentication type. If the user has a database password, run ALTER USER user name NO AUTHENTICATION.