WC Autocomplete not working with Paypal

Hello,

I followed all the steps in the Autocomplete documentation, but I am still not getting an automatic COMPLETED status. The orders are still all pending payment

Here are the steps I completed:
1) Installed the plugin and set tested the settings on both All paid orders and only Paid Virtual/Downloadable
2) Followed the steps in the paypal account to turn on autoreturn, add a thank you page url, turn Paypal Data Transfer ON and then copy the token.
3) In WooCommerce setting, I enabled Paypal standard, and added the PDT token in the correct field.
4) In the product, I tested with checking both Virtual and Downloadable items in the Advanced settings, and tried with just Virtual checked.

So I am not sure what is still missing here. Any insight would be appreciated. Thanks.