after the Pis get loaded with Cayenne,
they need to do a reboot.
A reboot may take 4 or 5 minutes on a Pi3,
particularly if you have slow memory.
-after you let it sit a while, (10 minutes)
-can you do a refresh to your dashboard?
I'll work with you here...
I have several Cayenne devices online.
I'm thinking of making an endless loop cycle on 1 of the devices,
just to ensure Cayenne connectivity.
-you never know when the server may go down.