If you are getting this screen shot below
Please check your app permissions:
If Apple Health is not correctly reflecting what your Garmin wearable (via the 'Connect' app) or your Apple Watch step count says, your STEPtember steps will appear incorrectly, as our App will pull the incorrect Health App data.
You can resolve with the following steps.
Note: This works for any 3rd party app / wearable that is syncing with Apple Health.
Open Apple Health and Select the 'Summary' page
Then tap on 'Steps' and scroll all the way to the bottom of the screen and select 'Data Sources and Access'
Scroll down to 'Data Sources' you can see that Connect (the Garmin app is second on the list)
Tap 'Edit' and 'tap and hold' the 3 bars to move it up in to first place and tap 'Done'
Apple Health App will now preference step data from whichever app is sitting in top spot.
HOT TIP: Always ensure your wearable app is synced with Apple Health each time before you sync with STEPtember App, this will ensure the most accurate data.
Note: This only works for STEP counts and will not convert other activities into steps e.g. cycling or swimming. These activities need to be entered via the manual activity upload.