1) Did you check the notification preferences *of forums* of the relevant users?
Dashboard -> User menu -> Preferences -> Notification preferences
BTW, The default preferences for users are determined here:
Site administration ->Messaging -> Notification settings
2) Did you check their "Forum preferences" in their user profile?
I encountered a "strange" issue in the past, where the "Email digest type" field was set to "Complete" or "Subjects". However, since the "Subscribed forum digests" option in the "Notification preferences" page was set so e-mails won't go out for digest, a user didn't get e-mail messages.
Dashboard -> User menu -> Preferences -> Notification preferences
BTW, The default preferences for users are determined here:
Site administration ->Messaging -> Notification settings
2) Did you check their "Forum preferences" in their user profile?
I encountered a "strange" issue in the past, where the "Email digest type" field was set to "Complete" or "Subjects". However, since the "Subscribed forum digests" option in the "Notification preferences" page was set so e-mails won't go out for digest, a user didn't get e-mail messages.