Unable to authorise ArcGIS 10.3 installation

[DanielleEvanson]

I'm sure this is a very simple question, but I've searched ArcGIS Administrator and Help and Support&Services to no avail.

I've installed ArcGIS 10.3 (Education trial, single use) but when I try to run ArcMap I get the following message: license manager running on host "Not_Set". When I go to ArcGIS Administrator it says "Not_Set" is an invalid host name, takes me to a box about concurrent use license and says I have 0 licenses and 0 available for ArcGIS Desktop Advanced 10.3.1. When I click on the data licenses box it is blank. See attached screenshots.

Not sure if my network administrator selected the wrong type of license; he doesn't think so.

Do I deauthorise? Uninstall? WIll my authorisation code still work?

[DanielleEvanson]

Thank you thank you everyone!! The ArcGIS Adminstrator window was hidden behind lots of open apps and not appearing in the toolbar but as I was preparing to restart I saw it. And was able to authorise. ArcMap is now open. Thank you!