Cobra Forum

Question: Unable to access ASP.NET Settings of a domain in Plesk: Can't detect .NET version. Possible site does not use ASP.NET


Applicable to:

• Plesk for Windows

Symptoms

• Plesk Obsidian running on a Windows server
• The error message

aspnetcfg failed: Can't detect .NET version. Possible site does not use ASP.NET (Error code 1)
(https://pix.cobrasoft.org/images/2025/12/29/mceclip1.png)


is displayed in the Plesk GUI when:

- opening ASP.NET settings in Plesk at Domains > example.com > ASP.NET Settings.

- changing password of the main FTP user at Domains > example.com > FTP Access

- issuing a Let's Encrypt certificate for a domain.

- attempting to open the page Domains > example.com > Hosting & DNS > Hosting

• The affected website may also load with the following error message:

The page cannot be displayed because an internal server error has occurred.

Cause

Misconfiguration in IIS, during which both of the following settings are in place when checked:

.NET CLR version is set to No Managed Code in application pool settings of the website in IIS Manager > HOSTNAME > Application Pools > example.com.

Microsoft ASP.NET support is enabled in Plesk at Domains > example.com > Hosting & DNS > Hosting


Resolution

In order to resolve the IIS configuration issues, you should do the following:

1.Log into Plesk

2.Go to Domains > example.com > Hosting & DNS > Hosting

Note: If the Hosting tab is inaccessible, do the following to make it accessible:

  1.Connect to the server via RDP
  2.Go to IIS > HOSTNAME > Application Pools > example.com > double click on domain and switch the .NET CLR version from No Managed Code to .NET CLR v4

(https://pix.cobrasoft.org/images/2025/12/29/mceclip3.png)

3.Disable the option Microsoft ASP.NET support and click Apply.

4.Enable the option Microsoft ASP.NET support back and click Apply.