Click on the cog wheel (Tools) in IE11 and click on “Compatibility View settings” above “Internet options” in IE11 and add (Add) the address that your portal has (it is pre-filled), then the address moves down one step to the box “Websites you’ve added to Compatibility view”, then click on the button “Close”. After that you can try again. Sometimes you have to log out and log in again. Maybe it want to update DMK, if it is so, do that. Perhaps you have to close down IE11 to update the DMK kit.
NOTE: Remember that your portal have to be added under Trusted sites, otherwise the DMK won’t work.
See here how you do that here: Internet Explorer block windows from ProjectCoordinator
NOTE: In the latest versions of Internet Explorer 11 sometimes DMK won’t work despite our recommended changes. If that's the case, then please install and use ProjectCoordinator Desktop instead. You find instructions and links here: http://www.icoordinator.com/en/downloads