Is this the first time launching Pro/E or have you had success with this setup before?
Which version of Pro/E? if WF5 the license server needs to run FlexNET license manager
Are you trying to get the license through a firewall? like via internet?
It could be simply the license manager isn't running on the server after a restart. I'd start with the server, and use the license diagnostics. Also check your license file to be sure it's using the right server name if for some reason something change via hardware or something.
Anyways a few blanks you need to fill in to help more.