This mainly happens if you terminated a cpanel account and somehow the MySQL user was not deleted properly.
Solution : Try deleting the mentioned user.
Delete the user :
mysql
mysql > use mysql;
mysql > drop user testusr7@localhost;
OR
mysql> delete from mysql.user where user=’testusr7′;
You can aslo check this using :
select User, Host from user where User like ‘%testusr7%’;
Now try restoring/recreating whatever you were trying to do and see if you still receive the error.
If yes do
grep testusr7 /var/cpanel/databases/users.db
grep testusr7 /etc/dbowners
If the user exist in the above files, delete that and try again.
OR
create a cpanel user with name “testusr7777″.
Modify account and rename that to “testusr7″
Terminate the account from WHM
It fixed for me!!!