Start with quick checks: is the site URL right, are the database name, user,...

https://articlegrovey.com/s/f7bHQMD8_BtdkVsSJK2xT

Start with quick checks: is the site URL right, are the database name, user, and password right, and is your host up? If so, try deeper fixes, like a database repair. Contact hosting support if the server is down or your login details fail again.