To change the ASP.NET version used by this domain, perform the following steps:
1 - 1 - Logged in to Plesk, https://your domain name:8443.
2 - Go to Websites & Domains and locate your website's domain name.
3 - Click ASP.NET Settings.
4 - Click Change Version.
5 - Select The ASP.NET framework version.
6 - Click OK.