Follow these steps to change the redo transport user in the Data Guard configuration:
SYSOPERprivileges to this user and ensure that the standby database has applied these changes:
SQL> CREATE USER DGUSER IDENTIFIED BY SOMEPASSWORD; SQL> GRANT SYSOPER to DGUSER;
Don't forget that if the password expires periodically for this user, this will pose a problem in Data Guard redo transport. So ensure that the default profile does not include the
PASSWORD_GRACE_TIME settings. If it does, choose another profile for this user.