- Go to Dashboard > Content > Speakers.
- Click on the '...' next to your speaker. You will have to repeat this step per speaker.
- Select Edit Record.
- Tick the Active? box.
- Don't forget to hit Save.
Speakers also have to be attached to an active talk record. Head to Content > Talks to schedule a talk for them, or to make sure the talk they're assigned to is active (... > Edit Record).