Users should be part of the DailyBot team

The Follow-ups Skill sends team reports to the channel you have configured for each team.

The reports that are sent are the ones related to the users/members of that team, so it could happen that a user is part of the channel in Slack (or room in Hangouts) but however they are not members of the Team in DailyBot.

Please make sure you add the proper members to each team in DailyBot's web dashboard.