Check to see if chained ("stacked") dongles is the problem. When you have stacked dongles connected to the same port, the SNL Manager may not find the dongle for the SNL. Take off all stacked dongles and use only the SNL dongle to see if you have a problem with the specific dongle or with the way they are stacked. If the dongle still fails, see the next tip for a temporary solution.
If the dongle has failed or not arrived yet, you can install a temporary license.
When a license error occurs, the answer often appears in the <SNL_Manager_install_dir>\lmgrd.log file. In this example, the user probably tried to check out a SolidWorks license with the wrong version of the SNL file.
The problem might be with port settings:
Port settings between the license server and the license client might not match.
Additional port settings for multiple versions of SNL Managers might not have been specified.