Bartłomiej Piotrowski created an issue #535:
When a new tarball is uploaded, mirrorbits incorrectly redirects request to a fallback mirror which does not have the file yet. We should expose the FTP volume at download.gnome.org/fallback and use it as the only fallback mirror.
$ wget https://download.gnome.org/sources/evolution-data-server/3.39/evolution-data-server-3.39.3.tar.xz
--2021-03-12 09:43:29-- https://download.gnome.org/sources/evolution-data-server/3.39/evolution-data-server-3.39.3.tar.xz
Resolving download.gnome.org (download.gnome.org)... 8.43.85.14, 8.43.85.13, 8.43.85.29, ...
Connecting to download.gnome.org (download.gnome.org)|8.43.85.14|:443... connected.
HTTP request sent, awaiting response... 302 Found
Location: https://ftp.acc.umu.se/pub/GNOME/sources/evolution-data-server/3.39/evolution-data-server-3.39.3.tar.xz [following]
--2021-03-12 09:43:29-- https://ftp.acc.umu.se/pub/GNOME/sources/evolution-data-server/3.39/evolution-data-server-3.39.3.tar.xz
Resolving ftp.acc.umu.se (ftp.acc.umu.se)... 194.71.11.165, 194.71.11.173, 2001:6b0:19::173, ...
Connecting to ftp.acc.umu.se (ftp.acc.umu.se)|194.71.11.165|:443... connected.
HTTP request sent, awaiting response... 404 Not Found
2021-03-12 09:43:30 ERROR 404: Not Found.