License problems(IOS/Mac)

Hi guys,
I am trying to run unity and I have read a lot of forums and support pages to try and figure it out myself but there doesn’t seem to be anyone else who has written something about this problem.
Anyway.
I am just opening unity and I make a license and activated it. then it comes up with the following:

Machine identification is invalid for current license. For more
information see online help at
http://unity3d.com/unity/err/license

For assistance contact
support@unity3d.com

With two options at the bottom of the page:
“Re-Activate” and “Quit”

I click “Re-Activate” and the following pops up after a while of loading:

Failed to Re-Activate There was a problem communicating with the license
server, please try again later or
contact support@unity3d.com

Basically what I’m looking for is a way to reset the license so that I may try again. When I go to the top mac selection bar and click unity “Manage License” is unavailable…

Does anyone know how to fix this issue?

Thanks,
BENZ

Contact the support team, and send in your invoice number and serial. They’ll be able to help you. (Or visit the webstore, log in, and then deactivate the serial number there.)