ORA-12345: user string lacks CREATE SESSION privilege

admin

ORA-12345: user string lacksCREATE SESSION privilege in database link
(linkname string)
Cause: There are several possible causes for this message:First, you will get this
message if your username in the second database specified was not granted the
CREATE SESSION system privilege. Second, you will get this message if the
username specified in the connect string of the database link definition wasnot
granted the CREATE SESSION system privilege.
Action: Theaction you take depends upon the cause of the message: In the first
case, ensure that your username in the secondary database was granted the
CREATE SESSION system privilege. In the second case, ensure the username
specified in the connect string of the database link definition was granted the
CREATE SESSION system privilege in the secondary database.