Why does my internet connection consistently go offline at the same time every night?

What steps can I take to investigate and resolve the recurring problem of my internet going offline at a specific time every night?
Please help me to solve this problem
A few years ago I would have said run all the antivirus and spyware checks you can. Now I'd investigate that someone controlling your internet connection has set times you are allowed to use it.
One time I was having trouble keeping internet connection and happened to look out the window and saw a car parked just down the street. I happened a couple of other times but I subsequently moved. Hackers routinely target neighborhoods and places like hotspots at public locations like libraries and fast food restaurants etc. If you make a lot of money and are in a nice neighborhood it is always a possibility, although it is unlikely in your case if it happens at exactly the same time every night and you completely lose connection. Another possibility is someone nearby using something like an xray machine or some heavy industrial electronic device, otherwise, it would almost have to be something with your ISP.