Click , then select Activate/Reactivate a software license . Follow the prompts to finish the internet activation. 3. Clear the FlexNet Publisher Cache
The most common culprit for SolidWorks 2020 is an outdated License Manager.
Download the 2020 SNL Manager from the SolidWorks Customer Portal. Install it on the host server and reactivate. 2. Force a License Reactivation