I suggest you unplug your WiFi router for a few seconds. Then reset the iPad's network. Go to Settings-General-Reset-Reset Network Settings. You will need to reconnect the iPad to WiFi.
To reset (reboot) the iPad, you must hold the Home and Sleep buttons for several seconds until the Apple logo appears. You should ignore the "Slide to power off" arrow. The iPad will restart after a couple of minutes. Resetting this way will not hurt anything, and sometimes clears up mysterious problems such as yours.
If you only briefly press the Home and Sleep buttons at the same time, you should hear a click, and an image of your screen should appear in your Photos. This is NOT the same as resetting!