If your website cannot connect to the database, it may mean that the database failed to start. It may have crashed, and might be having serious problems. We are able to work with you to bring the database back up. This may involve recovering the data in case of a crashed database.
Some things to check:
Do you have a recent backup? Restoring from a backup is much faster than recovering data from a crashed database.
Do you have a failover server? Failing over to the other server would allow the service to continue to be available even if one of the databases has crashed.
Is your hosting company helping? Sometimes hosting companies promise to help, but whether they are actually able to do it is not always easy to establish.
Next steps: Call us. We have the skills to help in this kind of situation.