I got hit with it just now and I was wondering what’s going on. Here’s the FAQ page: https://www.bahn.de/faq/6-warum-kann-ich-sparpreis-tickets-nicht-mit-lastschrift-bezahlen
Machine Translation:
Why can’t I pay for saver fare tickets and a BahnCard 100 by direct debit?
There is currently an increase in fraudulent activity based on so-called phishing emails. As a precautionary measure for your protection, you cannot pay for Sparpreis tickets and a BahnCard 100 on this website and in the app using direct debit until further notice.
One now has to use PayPal or a MasterCard/VISA/etc-branded bank card.
That’s nothing new, it’s the case for several years now
Perhaps intermittently so? I have obviously booked tickets in the last year with direct debit. hence why I expected it to work this time too.
Then you probably booked a SuperSparpreis or Flexpreis
That’s likely.