When trying to create my account, I got an error like 'you need the xyz.pdf file downloaded' and then nothing happened.

Trying again, with the same phone number, I can't create an account, because it tells me:
'Diese Telefonnummer ist bereits bestätigt — du kannst fortfahren.' (the number is confirmed, you can continue), but I can't continue, as the 'continue' button is grayed out. :(