Incorrect wp-config.php Information
“Error establishing a database connection” is usually caused by an error in your wp-config.php file. Access your site in your FTP client. Open up wp-config.php and ensure that the following are correct:
- Database name
- Database username
- Database password
- Database host
Problems with Your Web Host
The next step is to contact your web host. The following hosting issues may be causing the problem:
- Your database has met its quota and has been shut down.
- The server is down.
Contact your hosting provider to see if either of these issues is causing your problem.
If you have checked wp-config.php for errors, and confirmed with your host for hosting issues, it is possible that your site has been hacked.