Windows node stopped working

Sorry it’s such a pain to figure out.
Are all the flakey devices at that same location with the at&t voip router?

If so, are you able to get any support from at&t? I’d start with: How do I allow ZeroTier through my corporate firewall? and then router config tips

Thanks.

No, the devices are scattered. Three are at my own office location behind a Ubiquiti router. Another one is at a location with AT&T fixed cellular service. Two others are behind Suddenlink cable modems.

In fact, today I’ve been onsite at the aforementioned AT&T voip router location with my laptop which is on every network I have. And at this moment I’m not finding any nodes that aren’t reachable.

If the router (any router) were blocking it I’d hope it would be doing so consistently. But I don’t observe that.