In Challenge, your commitment to the habit is required much more than when you track it as a normal habit on the Journal view.
There are rules you need to know:
You are limited on how many times you can skip a habit throughout the challenge is happening. The limitation of skip is set by the host.
If you fail the habit 3 days in a row, you fail the challenge. Remember to check-in your progress in challenge before the next day comes, or it automatically marks the day as failed.
There's no chance to get back and check in once a day has gone, so remember to check in your progress timely.