You may get the following error on your WordPress website:
Error establishing a database connection
The error refering to establishing a database connection means that your web server cannot connect to the database. Either you have put the wrong settings in the wp-config.php file, the network between the web server and the database server is down, has DNS issues or is firewalled or the database server is down.
To troubleshoot the error establishing a database connection:
Check that you can open a connection to the database using myPHP in the control panel.
Get the username and password for the WordPress database (make note of the database name)
Edit the wp-config.php file and enter the correct database name, username and password to access the database
If you still get Error establishing a database connection, then you need to contact your host for support.