Start by checking your database credentials, server status, and recent changes....

https://simonsnewchat.rivetgarden.com/posts/how-do-i-prepare-a-timeline-for-my-criminal-lawyer

Start by checking your database credentials, server status, and recent changes. If those quick checks fail, try deeper fixes like repairing tables or reviewing wp-config.php. Contact your host if the database server is down or you still can’t connect.