Next, we can see how to fix this error via SSH. However, the solution may be a bit complex.

1. Firstly, we have to connect to the server via SSH.

2. And create Plesk database backup. For this we can use the following command:

# plesk db dump > backup.sql

3. After that, depending on the RoundCube version. Furthermore, we have to check the database password in /usr/share/psa-roundcube/config/config.inc.php or /usr/share/psa-roundcube/config/db.inc.php using the following command:

# cat /usr/share/psa-roundcube/config/config.inc.php
$config['db_dsnw'] = 'mysqli://roundcube:password@localhost/roundcubemail';

4. Now copy the password and enter the Plesk database using the following command:

# plesk db

5. After that we can ensure that ’roundcubemail’ database exists:

ysql> show databa<"%roundcube%";
+------------------------+
| Database (%roundcube%) |
+------------------------+
| roundcubemail          |
+------------------------+
1 row in set (0.00 sec)

If we find the database missing, we must go to the first solution via the Plesk user interface and reinstall (remove/install) the RoundCube component. In case the database is present we can go to the next step.

6. Next, we must check whether the roundcube user is present. (Empty output means that the user is absent.)

We can use the following commands to check this:

mysql> use mysql;
mysql> select * from user where user='roundcube';

7. After that we have to create the user and assign a password (no need to create a user if already exists, simply generate the password).

We can use the following commands for this:

For MySQL 5.0/5.1/5.5/5.6 and MariaDB 10.1

mysql> CREATE USER 'roundcube'@'localhost';
mysql> update user set password=password('<password_from_config.inc.php>') where user ='roundcube';

For MySQL 5.7

mysql> CREATE USER 'roundcube'@'localhost';
mysql> SET PASSWORD FOR 'roundcube'@'localhost' = '<password_from_config.inc.php>';

8. Then we have to grant the necessary privileges using the following command:

mysql> GRANT USAGE ON roundcubemail.* TO 'roundcube'@'localhost';
mysql> GRANT SELECT, INSERT, UPDATE, DELETE, CREATE, DROP, INDEX, ALTER ON roundcubemail.* TO 'roundcube'@'localhost';
mysql> flush privileges;

If we get the “Can’t find any matching row in the user table” error while running the Grant command,  we can use the following command without the host:

mysql> GRANT USAGE ON roundcubemail.* TO 'roundcube';
mysql> GRANT SELECT, INSERT, UPDATE, DELETE, CREATE, DROP, INDEX, ALTER ON roundcubemail.* TO 'roundcube';
mysql> flush privileges;