Internet smears at exactly midnight, what to do?

I have had the problem since about December 21, 2019 that I have neither my LAN cable nor the WLAN Internet with my laptop. It is connected with the LAN cable and with WLAN stands for "Connected, no Internet". Nothing happens when I go into the browser, the internet doesn't seem to work.
But when I go back to my computer in the morning, my LAN and Wi-Fi work fine.

Yes. 24h forced separation.

Your provider connects you anew and gives you a new IP

Sometimes you can change this in the router, but that doesn't always work

The internet always works with my cell phone…

24 h forced separation
Either you do the separation manually at 3 a.m. If it bothers you less or you have to live with it for around 5 minutes (or less) at midnight to have no internet.

I doubt it.

You may not notice it so directly

Will that switch to mobile data?

How long does the service interruption take?
if it takes longer than 5 minutes, then they are probably building something…
unless it takes longer than 50 minutes, there's always something broken at night… You should report this to the ISP…
if it lasts less than 5min, then it is a measure to ensure that you do not get the feeling that you have a real internet connection with your own IP… LOL this time of the chicane can be put into the late hours of the night… Somewhere in the router settings…

Or that

The whole thing goes on a little longer, at least until 2 a.m., I haven't stayed up yet. And
The internet always works with my cell phone…

Hi

Which OS?

If Wi-Fi works (smartphone), your PC must also work.

The whole thing goes on a little longer, at least until 2 a.m., I haven't stayed up yet. And

The internet always works with my cell phone…

Then maybe your PC is blocked in the router?

Or something on the PC is blocking the Internet

And how does your cell phone go online?
via LTE? So regardless of the Inet connection of your laptop?
once said "in the know" at the ISP?