If you are seeing an error on the payment page with a similar text like the one below, please check whether your browser has an internet security plugin like e.g. the Safe Money in Kaspersky Internet Security software.
Our payment service Ingenico only accepts payment requests from https://i.materialise.com. However, these types of plugins – in some way – adjust the URL during the payment process which causes Ingenico to refuse the payment.
In Kaspersky Internet Security software, you can add https://i.materialise.com and https://secure.ogone.com to its Safe Money Database. How this can be done is explained here. Following these steps should enable you to pay on our website.