Did you get this sorted?
Looks like my BQM, and the problem was with the fibre optic connector on the box on the front of the house where it changes to co-ax. You'll have a big coil of thin fibre, and because its coiled it tugs on the connector slightly, it may not be seated properly.
If you look in it, there will be a little device with 3 LEDs, I think one's power, and one upstream and downstream.. something like that. If your upstream one is red, try moving the cables and connector so the fibre cable goes straight into the connector, rather than maybe being pulled at an angle like mine was.
I didn't have to touch mine for 2 years, then got similar issues to yourself, so it can happen out of the blue.