mariob0310

[fair hinge]

When I'm creating the session which generates the event I want to handle above, I'm also using code:
(...)
PaymentIntentData = new SessionPaymentIntentDataOptions
{
ApplicationFeeAmount = long.Parse($"{price.UnitAmount * 0.1}"),
SetupFutureUsage = "off_session"
},
(...)

[olive hatch]

You need to set the PaymentMethod (pm_123)
https://stripe.com/docs/api/customers/object#customer_object-invoice_settings-default_payment_method

at the customer's invoice settings

[fair hinge]

Well, I'll try with it, thanks