It's confusing because we did just that!
It sounds like maybe the scan you sent didn't quite meet the quality requirements, so they would like you to upload it again.
They do mention that the photo page needs to be all clear, so maybe in your previous scan something was covering part of the photo so it couldn't be seen clearly, or maybe the pages weren't scanned completely flat and part of the page is obscured.
Even if you think you did it properly the first time, don't think too much about it - just scan and reupload it again.