Having trouble with VivaWallet in Paymattic

Hello. We really need to use VivaWallet in Paymattic becase that is the only way to get the payment method Swish.

We have everything set up correctly, merchent ID etc. from our account on Vivapayments.com.

We have created added the payment method on Paymattic, created a a form with Vivawallet and a payment items.

When we test and try to pay we get the error:

invalid_request

In the console we can read a lot of cryptic things. Something about admin-ajax.php. Also there are a bunch theese messages (23) for different files: "was preloaded using link preload but not used within a few seconds from the window's load event". The referenced files are core WP and also Woocommerce and others. I save the log and can post it.

## Other messeges are

- A form field element has neither an id nor a name attribute. This might prevent the browser from correctly autofilling the form.

- The label's for attribute doesn't match any element id. This might prevent the browser from correctly autofilling the form and accessibility tools from working correctly.

- A <label> isn't associated with a form field.

VivaWallet has no clue so I'm asking here. The also say it's made for woocommerce.

Any ideas?