Come Monday morning everyone in my office is receiving the following error when trying to send an email:

Zimbra Collaboration Suite could not send message: mail.SEND_FAILURE
Method: SendMSgRequest
Msg: SMTP Server Reported: 452 4.3.1 Insufficient System Storage
Code: mail.SEND_FAILURE
Detail: soap: Sender


We are suppose to have unlimited space so I don't fully understand why it would be telling me we have Insufficient System Storage. If anyone can help please do! Our entire office is without email and for some reason it always gets put on me to fix it!!!! Disclaimer: I am a newb who is willing to learn.