Why is it I can only download from Play Store via Wi-Fi.

[AC Question]

Samsung Galaxy S6, went from lollipop to marshmallow. Can anyone tell me why I can only download or update apps from the Play Store via Wi-Fi ever since the marshmallow update. I can't use my data connection. Previously I was able to do this. I have my settings set to update via Data or Wi-Fi . Thank you for any help you can give.