"Your IMAP server wants to alert you to the following: Your account is currently not accessible via IMAP due to excessive usage. Kindly try after some time."

I use Outlook 356. I have also seen that it has been taking a very long time to sync one of my inboxes. 

I have seen some other posts where it is suggested that this message comes either when your have more than 10GB of mail or that you are send too much email. My mailbox has less than 2GB in it and I send and receive maybe 10 emails on a typical day. So far today I have received less than 10 and sent none. 

Please advise me as to what I can do about this problem. Currently I have to shut down Outlook for a while. 

Thank you,

Barry