Javascript Error on Checkout

After doing Payment with Klarna (entered date of birth and phone number and clicking ok in the klarna popup), the order gets created in the background and its registered in klarna.

The problem is, the customer never gets redirected to the order complete page because of a javascript error:

(index):7 Uncaught TypeError: Cannot read properties of undefined (reading 'success')
    at Object.complete (klarna-payments.js?ver=2.6.0:formatted:297)
    at c (jquery.min.js?ver=3.6.0:2)
    at Object.fireWith (jquery.min.js?ver=3.6.0:2)
    at l (jquery.min.js?ver=3.6.0:2)
    at XMLHttpRequest.<anonymous> (jquery.min.js?ver=3.6.0:2)
    at XMLHttpRequest.nrWrapper ((index):7)

Any help on this problem? Thanks