When you try to get connected to database through web administration in the Plesk panel, you might get the below error :
To resolve the problem you can either create a new user for the database and create it as the default database user or else upgrade the missing record in the Plesk database for database user associated with the database using the below actions :
Log into Parallels Plesk Panel database and discover ID of missing database record using the following command:
select db.name, dbu.login, dbu.account_id, a.* from data_bases db, db_users dbu left join accounts a on a.id = dbu.account_id where dbu.db_id = db.id and db.name = 'DB_Name';
Once account_id is found, create new record in table psa.accounts:
insert into accounts (id, type, password) values (XX, 'sym', '');
Now login to the Plesk control panel and assign a new password to the database user.