Our checks[1] don't seem to have any issues, but they only fetch the 'lastsync' file which is quite small. If the problem happens again, can you run `mtr --report --report-wide --show-ips --report-cycles 100 mirror.fra10.de.leaseweb.net` and then try downloading again?

I'll try to reproduce it myself, but I can't promise anything and without more information there is no point in telling leaseweb.

[1] https://www.archlinux.org/mirrors/leaseweb.net/1039/

I'm afraid I haven't been able to reproduce this problem yet. Do you still have issues with that mirror and if so, can you try to fetch the file from a different network/server/cloud vm at the time you are experiencing problems? I'm guessing that this may be an issue with your internet provider.

The problem still persist. I've updated my system around four times since reporting this, and I've encountered this problem twice. Trying to reach the same URL with curl on another network connection, works, but so does the pacman operation after Ctrl+C and re-running it. As said, it is intermitten.

I assume other mirrors work fine, because: The first time that this problem reared it's head, I changed to another mirror, and there were no problems. After changing back to using the fastest mirror (which happened to be this problematic mirror), the problem reared it's head again (hence, this bug report).

Regarding "it could be a problem with my ISP": Could be. Though I doubt it, since another person experienced the same error message with the same mirror (in the forum post that I linked to). Unless that person is in the same country as me (Finland) and has the same operator as me (Telia) and happens to be in the same network infrastructure segment or something similar. Too many conditions that should be true if you ask me.

As to what this problem could be?
My guess: The said mirror has front cache and backend servers(s). Uncached files are server from a backend server and then cached. Thus when someone has requested a file, it is cached, and everyone receives the file from the cache (the cache works correctly). I'd guess the backend server / one of the backend servers doesn't work 100% correctly (full memory? disk failing? who-knows-what).

You should use "sudo reflector --verbose -l 5 -p http --sort rate --save /etc/pacman.d/mirrorlist".
This command will update your mirrorlist with the best answer from the server.
If You want to have country "sudo reflector --country XXXX --verbose -l 5 -p http --sort rate --save /etc/pacman.d/mirrorlist".

Finally I'm also seeing this on one of our servers. I'll ask leaseweb about it.

Qucik status update: Leaseweb replied that they do not use a cache on their server, but they can reproduce the issue with HTTPS. HTTP works fine and they'll investigate further.

The same issue also plagues the Dutch leaseweb mirror: https://mirror.ams1.nl.leaseweb.net/archlinux/$repo/os/$arch

All symptoms are the same as described for the German mirror.

This appears to be an issue with HTTP/2 and libcurl/pacman. I've filed a bug with curl for starters: https://github.com/curl/curl/issues/3392

Leaseweb has disabled http/2 support on the fra10 mirror so you should no longer see issues there. I've asked them to keep it enabled on ams1 for now so that we have a server to test the fix with.

Fixed in curl 7.63.0-2 in [testing]