Nintendo Switch connects to the network device but then not to the Internet, what to do?

Thanks for reading, so:

I want to connect to the internet so that I can play something with my colleague, problem is, it just doesn't work. Password is always correct, it connects to the network device, but then it does not connect to the Internet (but it works for my college)

The network device is not under strain or something because we and even his sister can easily connect to the Internet on their cell phones. Do you know what the problem is and what I have to do.

Restart router

Connect times with a Lankabel and see if it works

What is your "network device"

What is a lankabel, my friend thinks his family doesn't have that: /

Fritzbox or something

So do not connect via Wi-Fi but via cable. There are also some people who block new devices or unknown devices in the router settings

Restart both

Oh well, okay. In any case, I'm known. I've been with him since 4:00 p.m. And I flew out around 10:00 p.m. We have been trying to patch it up since then, but really don't know what to do (that's why I'm here because you get mega answers quickly, thanks btw)

You can of course log into the Fritzbox and see what happens when your switch requests a connection. But the easiest for you is I think times to restart the router and the switch.

Omg finally worked, god bless you, good night!

Happy to have fun