This tool has been removed by Plesk and is no longer available. The only way to connect to your SQL database is via MSSQL Management Studio remotely. Click here on how to accomplish that.
MyLittleAdmin is a web application for managing MSSQL databases.
By design, when you access MyLittleAdmin in the Plesk control panel at Websites & Domains > Databases > MyLittleAdmin Plesk will automatically redirect you to https://mssql.yourdomain.com/silentlogon.aspx
If the redirect does not work you will need to access MyLittleAdmin by using the server's hostname and using port 8401.
You can retrieve your server's hostname in the Welcome email sent to you when you first signed up. An example using the server's hostname would look something like https://****.peopleshostshared.com:8401 (****.peopleshostshared.com is the server's hostname).