This is the most common cause. Antivirus software like often overreach. They see Lumion 12 trying to access an external server and assume it’s a "phoning home" trojan. They silently block the connection without notifying you.

Mara had been awake for three nights straight—two for deadlines, one for the uneasy hum in her chest she couldn't name. The Lumion render had to be finished by morning: a glass-and-steel pavilion she’d modeled for a competition that could change everything for her studio. The scene was right, the camera move perfect, and the materials finally catching the light the way she’d imagined. All she needed was to check the final render on Lumion 12.

Before altering your computer settings, verify if the issue is on Lumion’s end. Like all cloud-based licensing systems, Lumion’s servers undergo occasional maintenance or face temporary outages.

Mara’s team was asleep. The competition brief was in the cloud. There was no time to wait for support tickets to trudge through bureaucracy. She dug into the network stack: DNS, proxy settings, TLS certificates. Everything looked nominal. She then disabled her local firewall and antivirus for a test; Lumion still couldn't connect. She moved the laptop to her phone’s hotspot. Again, the app failed to reach the license server. The problem had migrated with her machine, like a shadow attached to the app itself.