Customer has moved licence server and user workstations to new domain. The user profiles are still on the old domain. Now Autodesk Products (AutoCAD and Inventor) are asking the licence server every time when started....
Domain changes can sometimes cause some weird cache issues. Make sure that the NLM is running on the server still and handing out licenses.
The clients need to be able to PING the server and obtain the correct IPv4 address. Then verify connectivity thru the firewall (as domain changes affects firewall settings) to make sure you can get to http://servername:2080 and http://servername:27000 in Internet Explorer.
And then, make sure the ADSKFLEX_LICENSE_FILE is set.