I'm on Windows and my licenses just don't work.
Most likely something is blocking the connection to the local or remote sesinetd.exe license server program. We have seen issues with security software such as Avast and AVG blocking Houdini. Please check your security software and please whitelist sesinetd.exe (TCP port 1715) and hserver.exe (TCP port 1714).
Ensure that the services HoudiniServer and HoudiniLicenseServer are in the running state in services.msc.
One way to test is through the Power Shell:
netstat -an | findstr 1715
The above command tests if the license server daemon is listening on the port.
Next launch the Command Line Tool shipped with Houdini (hcmd.exe) and type:
sesictrl ping http://machine-name:1715
Please substitute your machine name above where it says machine-name.
If this does not report back Successfully pinged, please check your antivirus/firewall settings.