Could be either, could be both.
Try a few things
Force quit your mail app. Double tap the home button. When you see the preview for the mail app, flick it up and off the screen to close the app. Then tap on the home page preview to exit the mode. Try to get your mail again.
If it persists you can try to delete and then readd your mail info. go into the settings, mail, contacts and calendars. Delete your mail from the iPad, exit out, go back in and re-enter the info then try to download your mail.
It may also be something you just need to wait for your mail provider to fix. I know my Yahoo occasionally messes up for a few hours/overnight, then fixes itself (When yahoo messes with the server your mail is on, you'll have issues until they stop messing with it)