Problems with Lightning WebLN Donate Button block

Hi,

I experiment issues using the Lightning WebLN Donate block.
I've connected the wallet to a BTCPay instance. I know it's deprecated but it suits my need for now...

When the user clicks on the button, the QR Code of the invoice is displayed.
After the payment, the funds come to my wallet but :
- QR Code stays here and no feedback is given to the user
- In the dashboard, transaction stays with "unknown state"
- No invoice generated in BTCPay

In BTCPay logs, I've these issues:
AuthenticationScheme: "Greenfield.Basic" was forbidden.
AuthenticationScheme: "Greenfield.APIKeys" was forbidden.

In the settings, it is said that "requires permission to "Create lightning invoice" (btcpay.store.cancreatelightninginvoice)".
Maybe another permission is needed ?

Thank you for your help !