By default, web statistics page protected with a login and password of the admin user of the subscription. Plesk also protects your WebStats and AWStats with password protection using FTP Users as well if you want to allow a user to access your stats without providing them with your admin user. You can turn off password protection by following these steps:
Step 1: Login to your Plesk Admin Panel and Click on Hosting & DNS from your Dashboard.
Step 2: Click on Hosting Settings.
Step 3: Scroll Down and UNcheck the box as indicated below:
NOTE: If you web site uses ASP.NET Core you may receive a 404 error when visiting your Web Stats. Please follow this article for a work-around if this occurs:
You receive a 404 Page Not Found Error when visiting the Plesk Website Statistics for your domain. - Knowledgebase - Adaptive Web Hosting