Hiccup hasn't been on for a week. I'm putting this one down to his hardware was probably dying and now it's died properly and he's waiting for parts.
Don't assume too quickly.
Maybe he is on holiday in the sun.
Maybe he is running a booth on a Christmas market and is half frozen.
Maybe he is climbing an underrated summit in the Anapurna and is completely frozen.
Maybe he is visiting a very close relative in Burgundy (a third cousin once removed) who teaches him how to make wine.
Maybe he has been abducted by visitors from Zeta Reticuli who won't release him until he has taught them how to make cheese. Hollandse kaas. De echte.