Hi, I have a problem with one of my email account in mozilla thunderbird. This particular email account, the sent items does not synchronize well with the server. When I first add this email account, the sent items would have no problem synchronizing for some weeks, and then it always suddenly stopped out of nothing. I have tried to delete account, and then re-add account, only to have sent items appear for a few weeks, and then stopped syncing again. the imap address is : imappro.zoho.com I have contacted zoho support team before, they have checked my thunderbird, and they think this error has something to do with thunderbird. Thanks.