Uh-oh, it looks like your site is having trouble connecting to the database! This is a common WordPress error, but don’t worry, we can fix it. Usually, it happens because of incorrect database credentials, a corrupted database, or the database server being down.

try this

1. Check your wp-config.php file: Make sure the database name, username, password, and host are correct.
2. Repair the database: You can add this line to your wp-config.php file and visit yoursite.com/wp-admin/maint/repair.php: define('WP_ALLOW_REPAIR', true);
3. Contact your hosting provider: If it’s a server issue, your hosting provider might need to help you out.