Usually there are road bumps to working with either Hotmail or Outlook.com, but now things are getting quite tricky.  Our company regularly prunes deleted and junk mail, and while we sometimes have problems with the Outlook.com account (sometimes it decides not to send anything out, giving us mailer demon messages instead, only to have actually sent the mail or working properly within an hour or so), right now we are experiencing some worse-than-usual mailer demon problems.

Suffice it to say, sending out e-mails with photographs gets us the failed to send mailer demon notes, and we are unable to send ANY e-mail to ourselves (to the same e-mail, that is).

We've cleared the caches, turned the computer off and let it rest, sent multiple tests to other e-mails (including to the troubled e-mail itself) and the issue has presented itself on two separate computers.  We've also delved into the settings, thinking something might have been changed, but it remains the same as before the troubles began.

Is this just a passing issue with Outlook.com/Hotmail, or is this a persistent  issue?