Alternatively, if you would rather use PowerShell instead of Command Prompt, right-click the Windows Start menu, and click Windows PowerShell (admin).

In order to open the Command Prompt as an administrator, your Windows user account must have administrative privileges.

Alternatively, you can click Stop and then Start in the “Manage Website” menu to restart a website. [2] X Research source

If this doesn’t fix the problem, try restarting all the other application pools in IIS manager.