to eliminate alot of possibilities, I'd have both the mini and host connect and download an update, wait for them to process and then reboot both.
I'd also reboot all networking equipment.... modem, router, switches, etc.
Beyond that, I'd tell us all of your equipment and how its all connected to stimulate more suggestions.
-Roamio Pro/Slide Pro
-Stream (Gotta go unplug the sucker one of these days!)