[NSFW] Problems with multisite

Hi!

I’m trying to get the Payson checkout to work in a multisite.
Using the latest version of WP 5.7.2, Woo Commerce 5.4.1 and Payson Checkout.
No other plugins activated.

After I have filled in the checkout form, selected Payson, accepted the terms and click complete purchase I get this:

“Fatal error: Uncaught Error: Cannot use object of type WP_Error as array in /var/www/clients/web84/web/wp-content/plugins/krokedil-paysoncheckout-20-for-woocommerce/classes/requests/checkout/class-paysoncheckout-for-woocommerce-update-reference.php on line 24”

If I click back in browser I get to the payson page where I can fill out all the info and make a payment. But instead of get the thank you page / order completed The checkout only reloads and hides the Payson fields.
The button to switch payment method doesn’t work either.

I installed a single site and did the same and everything works fine..

I can’t figure out whats going wrong and would appreciate any kind of help!

Regards,
Mats