Class SMTPRecipientsRefused

              object --+            
                       |            
exceptions.BaseException --+        
                           |        
        exceptions.Exception --+    
                               |    
                   SMTPException --+
                                   |
                                  SMTPRecipientsRefused

All recipient addresses refused.

The errors for each recipient are accessible through the attribute 'recipients', which is a dictionary of exactly the same sort as SMTP.sendmail() returns.