Start with quick checks: confirm your database details and check for a hosting...

https://bluecircuitry.com/s/4wc0kzo4YXp2auCzXU6Vl

Start with quick checks: confirm your database details and check for a hosting outage. If those look fine, move on to deeper fixes, like repairing the database or checking server limits. Contact hosting support if the database remains unreachable.