Licence Removed??

I think that the SimSig system has just thrown a wobbly.

I'm playing the 2030 timetable, paused it to have some lunch and when I returned the game had stopped and my licence removed.
Why would this happen??
You can see from the screenshot that my licence was granted on 17th May 2021.
....

From what I gather the loader will check in with the license server every so often when a sim is running (possibly every 5 minutes, Realtime) to see if you are running a sim you have a license to. If it happens that when it checks in it cannot reach the license server for whatever reason it will take an make a save and then force quit the sim.

Your loader may not have been able to reach the license server because
-it was offline for maintenance (EPS's response seems to indicate that the license server was up at the time & I think they are part of the server team)
-your home internet dropped, even briefly
-your network adapter was not connected to the network, but machine was on (when resuming from sleep it takes a couple of moments for the network adapter to wake up and then connect to the network again.)

I'd guess the it was most likely the third of those above options that happened.
Your computer went to sleep while you were at lunch, making the wokeup.ssg as it went to sleep (probably a save to protect against power loss in sleep)
On waking back up, the Wi-Fi card took a couple of moments to connect to the network and thus the internet (likley whilst the windows lock screen loaded), during this time whilst your PC was awake but the network card was not connected to the network the license check-in happened and it couldn't reach the server to see if you have a valid license, so force quits.

I believe that in THIS thread OP was complaining about the same license server check-in mechanism, but under different circumstances. I've noticed the force quitting due the license server being unreachable quite a bit lately on my laptop too, it would be nice if it was a bit more resilient/lenient about not being able to reach the license server and force quitting. It feels like there has been a change to this in the past 45 days, there must have been a reason for the change, but I doubt the core code team will comment on it in this public forum.

Locking the license to that machine would definitely prevent this happening, but isn't convenient.