I've been having issues with WLM since December.  I have a gmail account and run on Windows 8.1.  I've been a part of other threads.  I've tried some of the posted solutions, but have not resolved my issue.

 I can receive emails.  Some messages will send, but not if they have attachments.  

 I don't get an error.  I get a message that says, "The message could not be sent.  A problem has occurred.  Try again. "

[Original title: Windows Live Mail 2012]

Moderator note: Posts from an unrelated thread merged with this one to avoid confusion