I encountered an issue when I first got my mesh devices a few weeks ago, where I could never get endpoints to join a mesh hosted by either an Argon or a Xenon/etherwing combination – they would fast-blink green forever, even though the gateways would connect fine. To make a long story short, the firmware team sent me a test build of Device OS late last week for the Argon (gateway) that fixes this (something about a bad IPV4/IPV6 interaction, or something like that ). A release candidate with that fix should be out “soon” (in the next few days – I’m hoping this week).
My router is an Arris TG1682G (identified by a sticker on the bottom of the router). So if you have one of those, you will probably have issues.
We have not identified/encountered this issue with other brands/models, but that doesn’t mean that there aren’t others… Early days yet.