Why wont the Play Store work on my Samsung Galaxy Tab 3?

when I go into the play store it said "no internet connection" so I go to my settings and I have the internet connected. well why wont it let me download apps

I am very mad so I made my Samsung galaxy tab 3 forget my user and everything on my play store. So I go and I click another WiFi connection and I have it. but before I made my tablet forget everything after I get a new connection I go back to the play store and I said the same thing "no internet connection"

and now I have everything lost and i made a new one but it said the same thing "NO INTERNET CONNECTIONS"

WHAT DO I DO KNOW