Outlook.com won’t send or receive emails with attachments in them. Help please :)!

My outlook.com account wont send OR receive emails with attachments beginning about 5 days ago.  I have tried different browsers (Internet Explorer, Firefox) and have had people from several different email accounts (and different hosts like Yahoo) try to send me emails with attachments of varying size and type.  They all get a Delivery Status Notification Failure notice.  There isn't a code in that email or anything.  It just says that delivery to the email has failed.  And when I try to send an email I get the same notice.  I can't figure out what to do.  It's worked fine for the last 3 years but now all of the sudden I can't get any emails with attachments and I can't send any emails with attachments.  Help please :)!