This problem has been there for long (version 8 and up at least). It simply dont not work for me to download. My distro version (kubuntu) failed immediately on “Lenox Acoustic” and “Electric Guitar” downloads (and only those) The app downloaded from Ardour always failed after some small percentage (also only on those). Using Wireshark I saw that it failed with multiple "TCP 74 56138 → 443 [RST] Seq=2 Win=0 Len=0. I suspected that that meant some problem with my router so I connected a cable instead. Using cable the download at least runs longer but still fails. My conclusion that it is a router problem but only for some downloads (seems odd though).
I am sure that others encounter this problem so post might give some guidance.
Could be but that does not explain why others, like Negus First Afrobeat, works fine. All electric guitars fail, regardless of size. For me these downloads fail at the exact percentage every time. Some day when I buy a new router I will try again.