Why does the app not allow me to import certain activities from a third party app?
It is up to the challenge organizer to decide which activities are enabled for your challenge. If an activity such as steps is not enabled, you will see them as “Unrecognized activity” and you will not be allowed to sync them.
Some challenges don’t allow importing steps or other activities as the challenge may only promote conscious workouts such as walks or runs. Importing daily steps that also include all the steps you take at home is therefore not enabled.
You need to reach out to the challenge organizer to inquire if a new activity may be added as it is not in the discretion of atlasGO to decide which activities are enabled for each challenge.