Cause: There are several possible causes for this error. First, you can get this error if your username (and password, if you are using database instead of operating system authentication) in the secondary database are not identical to your username (and password) in the primary database. Second, you can get this error if your username in the secondary database is invalid (has not been created). Third, you can get this error if the username/password combination specified in the connect string of the database link definition is invalid (either not created or has an invalid password).
Action: In the first case, ensure that the secondary database contains a username (and password, if you are using database authentication) identical to the one you are using in the primary database. In general, you should always use operating system authentication in Trusted ORACLE (see the Trusted ORACLE RDBMS Guide to Security Features for more information about the advantages of OS authentication). In the second case, ensure that your username in the secondary database has been created. In the third case, ensure that the username specified in the connect string has been created in the secondary database.
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