Why does the Internet disappear at night?

Question

Computer networks

Good afternoon. The essence of the problem:
there is a server that receives data 24/7 via the Internet;
there is a router that distributes this Internet;
at the end of last week I moved the router from one room to another, tk. there was not enough provider cable, connected it through a barrel (rj-45 connector). At first, there were problems with this barrel;
before that, there were no problems with the connection, but now the Internet began to disappear and turn on itself, and during working hours (8-17) everything works stably, and it starts to disappear closer to the night. The day before yesterday it turned off at 19:30, yesterday at 21:30 and closer to the morning it turns on itself, at 6:10 it was not yet, at 7:30 it already appeared.
I looked in the system events - the computer did not restart. The router is on the window, it was unlikely to get out of the socket.
Tell me, please, what could be the problem?
UPD: I called the provider, he said that there were no problems and failures on their part
UPD2: the system log in the router is stored until the next shutdown, as the TP said (verified by reboot), so the option that the router was turned off by third-party forces like brownies and watchmen disappear )
UPD3: yesterday I replaced the barrel with a new one and tightened it with a coupler so that it would not come out of the connector with all its desire (although the previous 2 were also new); pinging once a minute showed that only 1 disconnection with the router was per night and 5 with Google, which, I think, is quite within the normal range; I will continue to monitor

Answer 1

• Install a program like PingPlotter ( paid or torrents ).
  По сути это обычный трейс в ретроспективе, только красивый.
  

Answer 2

look at the logs of the router, if any, for the disappearance-appearance of a signal to begin with. In general, nothing prevents you from calling the provider's technical support in parallel with the questions on the toaster.

Answer 3

Instead of a barrel, make the most common twist, just unwind 5 centimeters, after isolation, you can twist back carefully. It works substantially better than barrels.