Sofortüberweisung points out that the logins to banks have changed after a new law in the EU.
The banks must then add an additional authentication step, the so-called second factor, to the login to your online banking.
This means that, in addition to your previous password, you must authenticate yourself with your bank in another way. Just like with your normal online banking, the latest version is also available.
Of course, this step is also necessary for the payment by Sofortüberweisung, because this is nothing else than the forwarding to your online banking.
Some banks require linking to a cell phone or smartphone. After the login data, for example, your bank will send an SMS with your mtan to your mobile phone, which you must enter into the screen mask to log in to online banking.
If it is not initiated, you cannot log into your online banking system and pay.
However, your bank should already have informed you about this change. Only with this new authentication can you use your online banking again. For further information, please contact your bank.