Seeing an “Error Establishing a Database Connection” screen means your core PHP codebase cannot authenticate directly against your MySQL server. This completely blocks front-end content loading and locks you away from admin dashboards.
Verifying Your Credentials
Open your file server using an FTP client or hosting File Manager panel and check your wp-config.php credential assignments. Ensure that your DB_NAME, DB_USER, DB_PASSWORD, and DB_HOST parameters completely match up with your live hosting environment data sets.