I was out of balance with my server payments and after the payment it still shows "Error establishing a database connection" and I cannot access my website.
How to restart the server or whats wrong.
Restarting Apache and mysql did not help.
This error generally indicates that your MySQL service is not responding. If no changes were made to WordPress' wp-config.php then the MySQL service is the place to start.
You mentioned already trying to restart MySQL, this can be done with the command:
service mysql restart
If you continue to see the error message, I would then recommend checking the files in /var/log/mysql/ as there is likely an error recorded there. If you can share any error message you find there with us we can figure out the next step.
I made changes in wp-config.php before but I edit the changes back because it did not work right now. I tried to change the domain settings.
service mysql restart - not working. Only sudo command is working.
If I try to access /var/log/mysql/ then messages appears:
Error: Directory /var/log/mysql: permission denied
Error: Failed to retrieve directory listing
I was able to accès log files from FileZilla.
I used Terminal and command sudo cat /var/log/syslog to access the file.
Jul 6 07:04:19 wordpress-1gb-ams3 /etc/mysql/debian-start[24583]: Upgrading MySQL tables if necessary.
Jul 6 07:04:19 wordpress-1gb-ams3 /etc/mysql/debian-start[24586]: /usr/bin/mysql_upgrade: the '--basedir' option is always ignored
Jul 6 07:04:19 wordpress-1gb-ams3 /etc/mysql/debian-start[24586]: Looking for 'mysql' as: /usr/bin/mysql
Jul 6 07:04:19 wordpress-1gb-ams3 /etc/mysql/debian-start[24586]: Looking for 'mysqlcheck' as: /usr/bin/mysqlcheck
Jul 6 07:04:19 wordpress-1gb-ams3 /etc/mysql/debian-start[24586]: This installation of MySQL is already upgraded to 5.5.49, use --force if you still need to run mysql_upgrade
Jul 6 07:04:19 wordpress-1gb-ams3 /etc/mysql/debian-start[24597]: Checking for insecure root accounts.
Jul 6 07:04:19 wordpress-1gb-ams3 /etc/mysql/debian-start[24602]: WARNING: mysql.user contains 3 root accounts without password!
Jul 6 07:04:19 wordpress-1gb-ams3 /etc/mysql/debian-start[24603]: Triggering myisam-recover for all MyISAM tables
Jul 6 07:09:01 wordpress-1gb-ams3 CRON[24804]: (root) CMD ( [ -x /usr/lib/php5/sessionclean ] && /usr/lib/php5/sessionclean)
Jul 6 07:17:01 wordpress-1gb-ams3 CRON[24846]: (root) CMD ( cd / && run-parts --report /etc/cron.hourly)
Jul 6 07:39:01 wordpress-1gb-ams3 CRON[25117]: (root) CMD ( [ -x /usr/lib/php5/sessionclean ] && /usr/lib/php5/sessionclean)
Jul 6 08:09:01 wordpress-1gb-ams3 CRON[25569]: (root) CMD ( [ -x /usr/lib/php5/sessionclean ] && /usr/lib/php5/sessionclean)
Jul 6 08:17:01 wordpress-1gb-ams3 CRON[25683]: (root) CMD ( cd / && run-parts --report /etc/cron.hourly)
I got mysql error also
sudo cat /var/log/mysql/error.log
160706 7:04:15 [Note] /usr/sbin/mysqld: Normal shutdown
160706 7:04:15 [Note] Event Scheduler: Purging the queue. 0 events
160706 7:04:15 InnoDB: Starting shutdown...
160706 7:04:17 InnoDB: Shutdown completed; log sequence number 59577283
160706 7:04:17 [Note] /usr/sbin/mysqld: Shutdown complete
160706 7:04:17 [Warning] Using unique option prefix myisam-recover instead of myisam-recover-options is deprecated and will be removed in a future release. Please use the full name instead.
160706 7:04:17 [Note] Plugin 'FEDERATED' is disabled.
160706 7:04:17 InnoDB: The InnoDB memory heap is disabled
160706 7:04:17 InnoDB: Mutexes and rw_locks use GCC atomic builtins
160706 7:04:17 InnoDB: Compressed tables use zlib 1.2.8
160706 7:04:17 InnoDB: Using Linux native AIO
160706 7:04:17 InnoDB: Initializing buffer pool, size = 128.0M
160706 7:04:17 InnoDB: Completed initialization of buffer pool
160706 7:04:17 InnoDB: highest supported file format is Barracuda.
160706 7:04:17 InnoDB: Waiting for the background threads to start
160706 7:04:18 InnoDB: 5.5.49 started; log sequence number 59577283
160706 7:04:18 [Note] Server hostname (bind-address): '127.0.0.1'; port: 3306
160706 7:04:18 [Note] - '127.0.0.1' resolves to '127.0.0.1';
160706 7:04:18 [Note] Server socket created on IP: '127.0.0.1'.
160706 7:04:18 [Note] Event Scheduler: Loaded 0 events
160706 7:04:18 [Note] /usr/sbin/mysqld: ready for connections.
Version: '5.5.49-0ubuntu0.14.04.1' socket: '/var/run/mysqld/mysqld.sock' port: 3306 (Ubuntu)