If SQL Monitor is configured to authenticate users with Active Directory, and you're locked out of your Active Directory service account, you need to switch the authentication mode back to the default, restart the Web Service (or website, if you're using IIS), and then switch back to Active Directory authentication.

You won't be able to log in to SQL Monitor (even as an administrator) to switch the authentication mode back to the default. Instead, you need to run a SQL script to do this.

1. Switch the authentication mode back to the default:
   1. In Management Studio, connect to the SQL Server instance that hosts the SQL Monitor database.

   2. Paste the following SQL script into a new query window:

DELETE FROM settings.KeyValuePairs WHERE [KeyName] = 'AuthenticationType';
DELETE FROM settings.ActiveDirectoryDomains;

1. 1. Run the script against the SQL Monitor database.

2. Restart the Web Service (or website, if you're using IIS).
   To restart the Web Service: from the Start menu, open Services, right-click SQL Monitor Web Service, and select Restart.
   To restart the website (if you're using IIS): open IIS Manager and, under Connections, right-click the website SQL Monitor uses. Click Manage Website, and select Restart.

Switch back to Active Directory authentication.


See also
https://documentation.red-gate.com/sm/troubleshooting/can-t-log-in-to-sql-monitor-with-active-directory/incorrect-service-account-credentials