Email not working on iPad

Hi. I got an iPad Pro 9.7 this September. It has been working well until recently email stopped working on it. The built in Apple email app has stopped syncing. And I have been unable to see any emails received since January 22nd. I tried deleting my email accounts but now it's not even letting me log into them again. The emails that I had signed into on my gmail app also stopped working I tried uninstalling and reinstalling the app many times but it doesn't even let me log into my email accounts. An error message says please go back....please help me!