SharePoint 2013: The tool was unable to install Application Server Role, Web Server (IIS) Role

Case

When we run the SharePoint 2013 Pre-requisites installer in order to prepare our machine to install SharePoint 2013 product installation on Windows Server 2012, the installer fails due to the error shown in the screen below

The error occurred due to the reason that your operating system Windows Server 2012 do not allow application to connect to internet straight away to download files necessary for installation.

Solution

In order to fix this this error, some steps needs to be taken as described below:

1. Open a MMC console
2. Add the Group Policy Object snap-in
3. Following screen will open
   
4. In Local Computer Policy go to Computer configuration --> Administrative Templates and select "System".
5. Scroll down the list in the System settings and find "Specify settings for optional component installation and component repair". Double click the settings, a screen as displayed below will appear.
   
6. Select enabled in the top left corner and select "Contact Windows Update directly to download repair content instead of Windows Server Update Services (WSUS)".
7. Click OK and close the MMC console.
8. Run the pre-requisite installer again and this time it will not give error on and server role installation.

You can also find the same article on Microsoft Technet