When trying to access your domain, you are receiving a login prompt for a username and password. If you click ‘cancel’ on this prompt, you will receive the following HTTP error:

HTTP Error 401.1 - Unauthorized: Access is denied due to invalid credentials.
Internet Information Services (IIS)

This indicates that the anonymous username and password configured in IIS for your domain are not correct. On a Plesk server, there is a tool included that will automatically resync this login information in IIS. To resync the anonymous username and password for one of your domains, issue the following command from a command prompt (replace yahoo.com with your domain name):

C:\Program Files\SWsoft\Plesk\admin\bin\websrvmng.exe —update-anon-password —domain-name=yahoo.com

This should resync the IIS anonymous username and password for the domain you specified, and you should no longer receive a login prompt when accessing your domain. You can also use this same tool to resync ALL of your IIS usernames and passwords for ALL of your domains at once. To do this, use the following command:

C:\Program Files\SWsoft\Plesk\admin\bin\websrvmng.exe —update-anon-passwords-all