First check the following:

1. Verify that you really need a second software license. In most cases, the existing license can be updated. If this is possible, create a C2V file and send it to Stromasys to receive a license update.
2. Check if you still have the fingerprint used to create the existing software license. If the system hardware has not changed, you can use the same fingerprint to create a second license.
3. If the state of the currently installed software license is invalid/obsolete/cloned, remove the license from the system following the steps described in Cloned Software License Removal.

Only if the steps above did not provide a solution, use the following steps to temporarily disable the software license, create a fingerprint, and re-enable the software license:

1. Stop all running Charon instances.
2. Open the Sentinel Admin Control Center (via VMM or point browser to http://localhost:1947).
3. Select the menu option Sentinel Keys.
4. Click on Certificates to the right of the software license.
5. Identify the path where the certificate folder is stored.
6. As Administrator go to the certificate folder and move the V2C files (certificate) stored there to another folder.
7. Restart the license service or reboot. To restart the license service perform the following steps as Administrator:
   1. Press WIN+R. 
   2. Enter services.msc in the input prompt and confirm with OK.
   3. Select the Sentinel LDK License Manager, right-click on it, and select Restart.
8. Use the License Update tool to create a fingerprint.
9. As Administrator go to the certificate folder and restore the certificate.
10. Restart the license service or reboot.
11. The software license should be back and work normally.