I recently came across Unknown SQL Exception 297 in the Event Viewer in two of my SharePoint Deployments. One with SQL 2012 and one with SQL 2008 R2.
Here is the full error message.
Unknown SQL Exception 297 occurred. Additional error information from SQL Server is included below.
The user does not have permission to perform this action.
3. Go in the Securables Section, Scrolldown and you will see the “VIEW Server State” , check “grant”
Uknown SQL Exception297 should stop appearing in your Event Viewer.
If this was helpful, say thanks in the comments :).