Just relaxing with the wife streaming a show when the internet cut out.
Immediately I noticed the line on the front of our XB8 router/modem was flashing with an amber colour, then flashing green.
After that, the light became solid white, but then went back to flashing white after a minute or so. No Internet connection at all since then. Seems as though something caused the router to reset/reconnect but it is not able to connect since then.