Since Mio Universal Channels connects other chat apps (Microsoft Teams and Webex Teams) to Slack, only the members native to your workspace are shown in the Slack app.
How to view all universal channel members
- Go to any one of your universal channels (not the direct message with the Universal Channels bot)
- Type the /mio members command and submit.
You should see a message listing the members of the universal channel. This message is only visible to you.