ControlPoint is not accessible and when attempting to access the page, you hit a "Server Error in '/' Application" error. After disabling the custom error in the web.config file, the error message below is shown:

This error can occur when the virtual directory for ControlPoint has not been defined or if a change in IIS has occurred that has removed the virtual directory definition.
This can be verified in IIS by expanding Sites and inspecting the icon used at the ControlPoint/_layouts/Axceler directory. If the Axceler directory appears as a folder, please perform the resolution below. If the icon appears as a globe, the virtual directory has already been configured.
Below are two methods to configure the virtual directory for the ControlPoint web application:


Once the virtual directory has been configured, the error should be cleared.