Q: Cannot get mail the connection to the server failed

Try to reset your device. This won't delete your data stored on device.

• Press and hold the Sleep/Wake button
• Press and hold on the Home button
• Keep holding both buttons until the display turns off and back on with Apple logo on it.

Alternatively, you may go to Settings - General - Reset - Reset All Settings

If this will not hiply my check this article:

Get help with Mail on iPhone, iPad, and iPod touch - Apple Support

Hope this will help