Mail Auto-Check not working

I have my mail accounts set to up-date every hour. But recently for the past few days I have noticed the accounts are not auto updating. Everytime I go to on of the mail accounts, at the bottom it says "last updated date/time". But the last update was the last time I was in the account. The only time it updates is when I open an account.

Is anyone else having this problem, or can offer a solution to it?