Ever since Windows 2003 Microsoft has implemented a facility which enhances the security of Internet Explorer.
As a general rule you should keep this security in place on servers but there are some instances such as remote desktop servers where you may want to disable this enhanced security.
The following instructions for Windows Server 2012
Instructions for Administrators
Log into your server as an administrator
Open up Server Manager
From the left menu select "Local Server"
From the pane on the right select the IE Enhanced Security Configuration by clicking on the word "On"
The following screen will open
Notice you will have the option of truning off the Enhanced security for either Administrators or General users or both
Press OK and you are done
Your users will most likely need to follow these next instructions
Instructions for End Users
Open up Internet Explorer and from the top right menu select "Settings" and "Internet Options"
Select the "Advanced" Tab
Press the "Reset" button
Tick the "Delete personal settings" option and press the "Reset" button
Internet Explorer will now be reset to it's initial settings
You may get a message stating that your server will need to be restarted. In most cases you can ignore this. Only advise your administrator to restart your server if you cannot browse the Internet normally