I have the Merchant ID filled in correctly, the API setup to allow billing_api1.playfab.com to handle Express Checkout, and the items are populated properly. It gets as far as bringing up the paypal window in a separate browser with the correct item, price, and vendor but no money is transferred when I pay. It goes the the PayPal Return link and thats it.
No errors in Unity or anything.
Unity 2017.3.0p3
Playfab 2.54.181105
TitleID: 2CF8