Hey all!
A team is looking into a potential issue with sending Messages to buyers via the Order view. Once I've got more information about this situation, I'll update this thread!
Thanks!
We've found the issue and are working on a fix for it now. Keep an eye out on this thread for an update once that fix is live!
And the fix is live! At this time, you should be able to send Messages from the Orders page without further issue.
Thanks!