Mac mail will not load emails anymore, just keeps "Loading..."

Hello,

For some reason, mac mail will not load previous emails. It is only one account, when I click on that mailbox, it just keeps "Loading" and never retreives emails. The acounts are fine. It was fine 5 minutes ago, now it is not. This has happened once in the past and it was never resolved. I recreated the account, and lost all the emails.

Please help!

Thank you,

Greg