Client-side troubleshooting:
: Go to the Server Administration tab and click Modify > Activate/Reactivate your product license(s) . restart and test. To resolve this
If none of the above work, the SolidWorks Licensing Service itself is corrupted. not just the workstation.
: If the service isn't running, SOLIDWORKS cannot validate the key. restart and test. To resolve this
After adding exclusions, restart and test.
To resolve this, you generally need to perform a on the license server itself, not just the workstation.