Lumion needs to validate the license online periodically.

: These often interfere with the connection to Lumion’s license server. Turn them off and try launching the software again.

A common "hidden" cause is a modified hosts file that prevents Lumion from reaching its home server. Open as an Administrator. Navigate to C:\Windows\System32\drivers\etc\hosts . Look for any lines containing the word "lumion" .

Good luck, and happy rendering.