> For the complete documentation index, see [llms.txt](https://docs.tryterra.co/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.tryterra.co/faq/help-topics/no-data/historical-backfill-returns-nothing/apple-health-historical-access-restricted.md).

# Why does Apple Health backfill return empty for a date range?

When a user first authorizes a new app for HealthKit, **iOS may restrict access to some historical data** even though the Health app shows it.

Have the user:

{% stepper %}
{% step %}
Go to **Settings > Health > Data Access & Devices** and find your app.
{% endstep %}

{% step %}
Toggle all data types off and back on.
{% endstep %}

{% step %}
Re-trigger the [backfill](https://docs.tryterra.co/health-and-fitness-api/managing-user-health-data/requesting-historical-data).
{% endstep %}
{% endstepper %}

If data does appear via the API but your query returns empty, check your date range and parameters, which is usually a query issue rather than missing data.