Another IT nugget for the MS admins out there. Microsoft has recently introduced an Outlook “Newsletters” service, solely intended to create and distribution internal newsletter emails to an organization.
As always with Microsoft, things aren’t always as they seem, and our newsletter editors struggled to send the edition. The error given was something along the lines of “list contains external contacts”.
After pulling my hair for an hour trying to find where it thought an external contact was (list was all internal), I noticed that since this is a web-only feature and available exclusively via Outlook Web Access, I jumped over to OWA and looked up the list. Sure enough, somehow its classified as “external”, despite even having the external contacts allowed checkbox to be off.
Thinking this is likely a bug/glitch, I figured I’d try the first dumb thing that came to mind; nesting the dynamic list within a static list. I did so and told the user to wait about an hour, then try it out. Sure enough, after some time, the newsletter delivered.
So if you’re having weird messages trying to send Newsletters via the Outlook Newsletter service, see if you’re sending to a dynamic distribution list, and if you need the list to be dynamic, just nest it in a static list.

