It has become almost routine to receive a "No Internet Connection" error message. When I check the upstairs PC the Internet is operating without problem. I do not know what to do or check on my iPad Air 2.
It's possible you may be routinely operating your Air2 at a distance that is further than the PC from your modem/router with the result that your iPad is not getting a sufficiently strong signal. Have you tried moving the modem/router closer or shifting your iPad viewing position?
Another option could be to buy a signal booster. They are not over expensive.
I haven't found a good similar app for iOS (my Air 2) but if anyone around you has an Android device there are a number of very good Android apps that will show WiFi signal strength at the current location. Really helped me determine that my old router had poor coverage in my house. I bought a new Asus router and now I have outstanding coverage throughout our 2-story house.