Unable to download a book

I tried to read some e-books with Adobe Digital Editions on my Mac, iPad and iPhone from the website https://www2.onleihe.de/goethe-institut.

Some books I can't download. The website is still the same.

Unable to download

Error getting License. Lisense Server Communication Problem:

E_LIC_ALREADY_FULFILLED_BY_ANOT_HER_USER

Could you please help me to understand the problem with downloading?

Thanks in advance