Why has my iPad stopped receiving emails?

My iPad has stopped recieving emails. The circle thing in the top left hand corner just keeps going round and round.

greanfz 2014-10-20 03:26:46 First, check your internet connectionThen, check if the mailbox is full ha14 2014-10-19 04:57:08 Get help with Mail on iPhone, iPad, and iPod touchhttp:// Jan F. 2014-10-19 01:59:51 I forgot, check your iPads storage. If there is not enough free space left it will also refuse to download further emails. Jan F. 2014-10-19 01:59:08 Have you tried restarting your iPad?Press and hold the Sleep/wake button until the slide to power off appears.Power your device off and then on again.Check the email accounts configurationSettings > Mail, Contacts Calendars and tap the account name following by tapping your email address, double check the settings and passwords.If it is a POP account make sure no other device is retrieving emails at the same time as the POP protocol will usually lock the mailbox allowing only 1 simultaneous connection.If you continue having problems note down the last email in your Inbox, log into webmail and try moving the next email to another folder. In rare cases an email can be corrupt in a way where a device or client is having problems downloading it.