Answer:
After the release of the new generation of Dlubal programs, including RFEM 6 and RSTAB 9, the Dlubal extranet layout was modified. The ability to download your authorization file (author.ini) is still possible. The file is now in a different location.
After successfully logging in to the extranet, you can follow this workflow selection:
Licenses → Authorization Files for Download | RFEM 5, RSTAB 8, …" → Autorization Files for Download …
The new generation of programs (RFEM 6, RSTAB 9, RSECTION) are entirely cloud-based, so they use online login for the authorization and no longer require the authorization file.