A SQL operation in the AD FS configuration database with connection string

Log Name:      AD FS/Admin
Source:        AD FS
Event ID:      352
Task Category: None
Level:         Error
Keywords:      AD FS
Description:
A SQL operation in the AD FS configuration database with connection string Data Source=np:\\.\pipe\microsoft##wid\tsql\query;Initial Catalog=AdfsConfiguration;Integrated Security=True failed.

Additional Data

Exception details:
A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server)

The ADFS service was stopped. Restarting it just gave errors.

Solution:

Restart "Windows Internal Database"

Restart ADFS