Quota = -1, but gets error: "maildir over quota"

This is the exact same issue that I am having. I have followed the steps given earlier, but it is still not working for me. Any update on how to push the mail through the queue?

Thanks for the help.

 

I went in and adjusted the quota on the accounts to be 100 mb. I waited for the queue to clear, and then I readjusted the quota back to 0.

Emails are going through now.