Here is what could be causing this error message:
1. Is your information in the correct format
Check out our help center article for more information
2. Do your column headers match ours?
Your census will not upload with different column headers!
2. Are you using the right template?
Make sure you are using our recommended census template - check out our help center article to download the single option template
3. Does your template have a formatting issue?
Here is our help center article to correct it.