Suddenly no WLAN connection on the laptop?

I just have an annoying problem and I don't know what the cause is.
My laptop with Windows 7 suddenly can't connect to my router anymore. "It was not possible to make a connection"
However, when I switch on the hotspot from my smartphone and then connect my laptop to the hotspot, it works perfectly. So it can't be the laptop.

But it can't be due to the router either, because I have no problem using the Wi-Fi with my smartphone.

What else can that be? The password stored on my laptop for the WLAN is correct. Restart brings nothing. I didn't change anything in the settings and I didn't download anything. Everything was okay yesterday. Do you have any idea what that could be?

I have the Connect Box from Unitymedia

There's a button on my laptop that can be used to switch Wi-Fi on / off. Give it a try.

Unitymedia likes to spin around from time to time, not very reliably. Strangely, it spares me first on the laptop, then only on the PC.

If you switch off the router again, wait 1 minute and restart and it doesn't get better, there's not much you can do but wait and see if it is up to you again.

What you can still try is to uninstall the driver for the Wi-Fi chip from the laptop in the device manager, then restart and reinstall. Then it should work again.

Because I like to spin around, I already had it, from one day to the next there's no connection.

I did that and it didn't work. As I said, I can connect to the hotspot from my cell phone. So if there was a general connection problem on the laptop, I could not connect to the hotspot. It just doesn't connect to my router, but my iPhone can easily connect to the router

Do you think uninstalling the Wi-Fi chip will solve the problem? Because as I said, if I turn on the hotspot from my iPhone and then connect my laptop to this hotspot, I can easily use the Internet. So you would suspect that it is not the laptop but the router, but why then do I have no problems surfing the iPhone with the WLAN?

I also tend to think less of it because of the laptop because I couldn't connect to anything at all, but it's worth a try.

Windows creates a so-called WLAN profile for each WLAN network.
In this profile Windows stores all the necessary settings (encryption, IP configuration, DNS, gateway and much more) for the respective WLAN.
If these settings are turbulent or different in the meantime (changed due to encryption or frequency band, router update, driver update, …) it can be wrong.

My proposition:

Delete the profile for your Wi-Fi in Windows and connect to the Wi-Fi freshly (you need the Wi-Fi key, because you know that).

Here are 2 ways how to do it, step by step:

https://tipps.computerbild.de/internet/verbindung/wlan-loeschen-mit-dieser-vorgehensweise-klappt-es-780959.html