RoundCube webmail is not accessible on Plesk: DATABASE ERROR: CONNECTION FAILED

1. Log into Plesk.

2. Go to Tools & Settings > Updates.

   

3. Remove the component Roundcube and then install it again.

   

   ---

   

Note: The solution may be a bit complex. Contact server's administrator or hosting support if required.

1. Connect to the server via SSH.

2. Create Plesk database backup, for example:

   # plesk db dump > backup.sql

3. Depending on the RoundCube version, check the database password in /usr/share/psa-roundcube/config/config.inc.php or /usr/share/psa-roundcube/config/db.inc.php:

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

4. Copy the password;

5. Enter Plesk database:

   # plesk db

6. Make sure that 'roundcubemail' database exists:

   mysql> show databases like "%roundcube%";
   +------------------------+
   | Database (%roundcube%) |
   +------------------------+
   | roundcubemail |
   +------------------------+
   1 row in set (0.00 sec)

   If the database is missing, go back to the first solution via Plesk user interface and reinstall (remove/install) RoundCube component. If the database is present continue this guide.

7. Check whether the roundcube user is present. Empty output means that the user is absent:

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

8. Create user and assign a password:

   Note: If the user exists already, it is only needed to generate the password. There is no need for the CREATE USER sentence

   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>';

   For MariaDB 10.5+

   MariaDB [mysql]> CREATE USER 'roundcube'@'localhost';
   MariaDB [mysql]> SET PASSWORD FOR 'roundcube'@'localhost' = PASSWORD('<password_from_config.inc.php>');

9. Grant the necessary privileges:

   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;

   Note: if "Can't find any matching row in the user table" error appears when running Grant command, use 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;