Please can anyone help.   Our inbox (Windows Live Mail 2011) received a large number of emails for failed delivery for emails we hadn't sent.   We are now unable to send any emails and everything comes back with the above message.   We have contacted our broadband provider but they were unable to help.  From other posts on this site it seems the issue can only be resolved by Microsoft - any help in sorting this out would be much appreciated.

[Moved from:  Windows / Windows 7 / Email & communications]