Internet Status: Not Connected even though a connection exists. How do I fix the error?

I have an existing Internet connection on my computer (Windows 7) with which I can use the Internet for example in the browser. However, in Java programs like Minecraft / TechnikLaunher, the "Unconnected" status is displayed time and again so that I can't use it. In addition, the bottom of the desktop at the Wi-Fi icon also shows "Not connected" (see picture). How can I fix the problem?

Restart the PC

Restart the wireless router

Remove network and add new

Do this here:

Press Windows + R
Enter cmd
ENTER
Now enter ipconfig in the window

And then post the result as a response.

You have to start by understanding that there's a difference between LAN and WAN (Internet).

Your computer is clearly connected to (D) a WLAN.
But that says nothing about your access to the Intenet.