outgoing mail has been blocked and trouble with outgoing attachments

outgoing mail has been blocked and trouble with outgoing attachments

My outgoing mail has been blocked.  How do I correct this?  I have been having a lot of problems with my Zoho account today via Outlook.  When I have been sending attachments, I keep getting a notice stating that it exceeds the limit and then the message keeps popping up.  I have had to delete my zoho account from outlook several different times today to get it to stop.