SumUp Payment Gateway : problems

Hello,

I am trying to use “SumUp Payment Gateway for WooCommerce”, but I have some troubles…

1. I can insert my credentials just fine (“your credentials are correct”), but at the same time I have three errors when I save it of ““Cannot modify header information …” type.

2. I can see the payment by card option at the checkout, but when I click on my “Order now / Pay now” button, the Payment card widget of Sumup doesn’t launch or appear.

Does anyone have experience with this plugin, and/or had the same troubles as me?

Thank you for your help!