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Issue:

When launching nTop or nTop Automate, the software fails to open, and the following error message appears: 
"A license is required to use ntop/ntopcl, but a valid license was not found.
If you do not have an active ntop/ntopcl license, please contact sales@ntop.com for more information. If you believe you're receiving this message in error, please contact support@ntop.com if you continue to experience this issue."

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Applies to:

  • nTop (Desktop)
  • nTop Automate (Command Line)
  • Network environments enforcing TLS v1.2

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Cause:

By default, nTop uses TLS v1.3 (Transport Layer Security) to connect to our licensing server for authentication. If your organization’s network security protocols are restricted to the older TLS v1.2 standard, the connection will fail, resulting in the “Valid license not found” error.

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Solution:

To resolve this, you must add a specific flag to the nTop executable to force it to use the older TLS v1.2 protocol. The easiest way to apply this change permanently is to modify your desktop shortcut.
  1. Locate your nTop shortcut on the desktop.
  2. Right-click the shortcut and select Properties from the context menu.
  3. Click on the Shortcut tab.
  4. Locate the Target field. You will see a file path ending in ntop.exe".
  5. Place your cursor at the very end of the text (after the closing quotation mark).
  6. Type a space, followed by --tls1_2.
Correct format: "C:\Program Files\nTopology\nTopology\ntop.exe" --tls1_2
  1. Click Apply, then OK, to save the changes.
Note: Ensure the flag is placed outside the quotation marks. If placed inside (e.g., "...ntop.exe --tls1_2"), Windows will treat the flag as part of the file name, and the shortcut will fail to launch. Running nTop Automate (nTopCL): If you are running nTop via the command line, you must append the flag to your execution command: ntopcl.exe --tls1_2