Possible cause 4 of 8:
You've established a connection to a Wi-Fi network but you're not logged on
Some Wi-Fi networks require that you log on.
What you need to do
Open the browser on your tablet and try to load a website. The browser is directed to the start page of the Wi-Fi network. Follow the instructions to log on.
If you can't log on to the Wi-Fi network, turn off Wi-Fi on your tablet and connect to the internet using the mobile network.
Did this solve the problem?