I’ve got a device that is showing as offline but it also is showing telemetry data for the past 24 hours. The device is also responding to ping so it seems to be on the network. I’m not physically at the same site as it until Thursday now so can’t check it in person but they said the screen was blank like it hadn’t come out of the suspension we had set up.
It seems the device (I assume it’s the Pi1) doesn’t correctly react to any remote request (like capturing a snapshot of its output, etc…) and instead instantly, but temporarily, loses connectivity and is marked as offline as a result. I’m not entirely sure what causes this and it’s not possible to debug remotely as that, well, requires it to contact from remote. Would it be possible for the staff at your site to power-cycle the device to see if that helps?
I’ve had someone check today and they said it is now playing video so hopefully it is working now. Still does like you said show offline when looking at it, but if its playing that is ok for now. We’re awaiting a newer model to replace it but obviously the shortages at the moment are causing issues!
Thanks
I think I found the issue. It seems that device doesn’t have a sufficient precise system time. This causes it to reject commands send by the info-beamer backend as those are considered “too old”. A backend change now increased the tolerance for that and the device is now reachable. This also allowed me to confirm the time issue: Your device is around 50 seconds in the future 
It seems the device cannot reach the default NTP servers used by info-beamer nor does your local network provide a local NTP server and thus defaulted to retrieving the system time via a one-time HTTP request shortly after starting up. I have the suspicion that the lack for correction via NTP causes the local system time to slowly drift until it got so far away from the real time that the problem above happens. I’ll have to think about how to prevent these issues from happening in that case.
For now you can reach your device. A Pi1 is fine for playing just video and image content, so there’s no need to hurry with switching it over to a more powerful model.