Can't connect to internet Lubuntu 18.04

Question

I can't connect to the internet with my Lubuntu 18.04. It shows the wifi adapter with the signal bars and says that it's connected, but Firefox says: can't connect to server and Sudo apt-get update says Failed to Fetch.

Answer 1

Take the following steps:

• open a terminal by pressing Ctrl+Alt+T

• In the terminal type:

  ping www.google.com
  

• You will probably get time out as reply or not a reply at all
• Press Ctrl+C to stop the ping command.

• In the terminal now type:

  ping 1.1.1.1
  

  This will try to ping Cloudflare's DNS. If you get replies then the problem lies within your DNS server.

If you don't get a reply then you are not connected to the Internet through your router. (which is en issue outside of Ubuntu and off-topic here)