The source code for the Adyen payment provider is open source and can be found here https://github.com/vendrcontrib/vendr-payment-provider-adyen so you could test that and see if it's something here that is at fault. If it's not though, and it is indeed Vendr sending you to the wrong location, I'd first of all double check our changelog to see if this is mentioned anywhere as resolved in future releases, and if so, upgrade (https://vendr.net/docs/core/changelog/) or if not, post this on the support forums with as much detail as possible to replicate the issue https://our.umbraco.com/packages/website-utilities/vendr/vendr-support/ Generally speaking though, Vendr should only send you to the error page if either the payment gateway sends you directly to it, or if the transaction status back from the payment provider is set to errored, so eiher way it sounds like a potential issue from the payment gateway setup. I'd also check the payment gateway portal to see if they log any errors against transaction so you can see any failing payments and why they are failing.