iCloud account on Mail is frozen

Hi there,

My (paid) iCloud account seems to be locked in Apple Mail (6.2). It will neither send nor receive messages. I removed the account from Mail, closed Mail, then re-opened it, the account re-appeared. Still the same problem.

I can access it and use it fine on the webmail side, just the Mail app that has this problem.

Suggestions as to how to get it running again, please?

Thanks.