POST https://api.mollie.com/v2/payments resulted in a 422 unknown response

[bartrylant]

Description

When using Mollie in Commerce 5, I get an error when trying to pay through Mollie. I'm using the provided example templates, so no errors on my side. I'm using a Mollie test api which is working perfectly fine on a Commerce 3 install. The payment options I activated in the Mollie dashboard all get shown, so far so good. So the api key works and I can retreive info from my Mollie account. It's when submitting the payment form, the error occurs. The error I get is:

Client error: `POST https://api.mollie.com/v2/payments` resulted in a `422 unknown` response: {"status":422,"title":"Unprocessable Entity","detail":"The webhook URL is invalid because it is unreachable from Mollie' (truncated...)

Steps to reproduce

1. Add Mollie as a gateway, fill in a correct api key
2. When checking out, select Mollie as a gateway
3. Select a payment option provided by Mollie
4. Click "pay"
5. See the error

Additional info

• Craft version: 5.4.1
• PHP version: 8.3.8
• Database driver & version: MySQL 8.3.0
• Plugins & versions: Commerce 5.1.0.1 & Mollie for Craft Commerce 4.2.0

[linear]

PT-2135 POST https://api.mollie.com/v2/payments` resulted in a `422 unknown` response

[bartrylant]

Looks to be a problem with calling the local webhook. The Mollie plugin for Commerce 3 didn't really care, but this one does.