Verify that your license details are correct and have not expired. Make sure you're using the correct email and password associated with your Lumion account.
Some antivirus programs prevent the license handshake because they monitor real-time data encryption. lumion is being prevented from contacting the license
Sometimes, network restrictions can prevent Lumion from contacting the license server. Try connecting to a different network to see if the issue persists. Verify that your license details are correct and