Here is a comprehensive guide to why this happens and how to fix it. Common Causes of the Error
Your license "bit" may need an update to support a newer version of the software.
AccuMark relies on a background service to "see" the license. If this service crashes, the software won't open. Press Windows Key + R , type , and hit Enter. Scroll down to find Sentinel LDK License Manager . Right-click it and select Restart . a valid accumark license was not found for this product
Ensure you are connected to the office VPN or local network.
Ensure the "Status" says and "Startup Type" is set to Automatic . 3. Access the Sentinel Admin Control Center Here is a comprehensive guide to why this
If none of the above steps work, the issue may be internal to the license itself:
Check that your Firewall isn't blocking port (the port used for license communication). If this service crashes, the software won't open
A physical USB device (often purple or green) plugged into your computer.