The HTTPS download site is much more reliable than the FTP one, but there are problems
in the directory listings. This works:
https://www.gnupg.org/ftp/gcrypt/gnutls/
Clicking "v3.4" on that page does not:
https://www.gnupg.org/ftp/gcrypt/gnutls/v3.4/
But the downloads in that directory are accessible:
https://www.gnupg.org/ftp/gcrypt/gnutls/v3.4/gnutls-3.4.9.tar.xz
The same issue shows on other directories of the same level, like:
https://www.gnupg.org/ftp/gcrypt/gpgme/patches/ https://www.gnupg.org/ftp/gcrypt/gnupg/unstable/