A corrupted or modified hosts file will instantly kill connections to *.lumion3d.net domains, regardless of your firewall setup. Action Required Important Rule
How do you resolve Installer (v2) problems - Installation issues?
Starting in late 2025, Lumion required users of older versions (like 12 Pro) to have their license keys registered to a . If you haven't done this, the server may reject the connection.
This also means Lumion . The error message indicates this communication with the license server has been blocked. A corrupted or modified hosts file will instantly
If you are on a restricted network (like an office or school), ensure your network administrator has whitelisted these requirements: : 443 (HTTPS) and 80 (HTTP). *.lumion.com *.lumion3d.net *.mylumion.com 5. Clear Startup Conflicts Run as Admin : Right-click the Lumion shortcut and select Run as administrator Force Startup CTRL + SHIFT
Add the temporary Lumion user directory: C:\Users\[YourUsername]\AppData\Local\Lumion 12.0\ 4. Verify Port 80 and Port 443 Accessibility
Navigate to your installation directory (usually C:\Program Files\Lumion 12\ ) and select Lumion.exe . If you haven't done this, the server may
Open > Virus & threat protection > Manage settings .
Therefore, the very first thing you must do is ensure your license is properly registered:
If your internet connection is fine and you're not using a proxy or VPN, the next most likely culprit is your security software. Firewalls and antivirus programs are designed to protect your computer, but they can sometimes be overzealous and mistakenly block legitimate applications like Lumion. If you are on a restricted network (like
Most connection issues are caused by overzealous security software blocking Lumion.exe .
To ensure you never see this error again next month: