This was a solution I discovered years ago when troubleshooting a customer’s database problem. The error thrown was:
The log for database ‘database_name’ is not available. Check the event log for related error messages. Resolve any errors and restart the database.
It was caused by the Auto Close database property being set to true. To rectify the issue, you will need to bring the database offline, bring it back online again, and then set the Auto Close property to false.