Build error: Failed downloading https://luarocks.org/mpack-1.0.8-0.rockspec -

I’m trying to build nvim 0.7.2. I checked out the relevant tag and then did

make distclean && make CMAKE_BUILD_TYPE=RelWithDebInfo

After a lot of output, I’m seeing

[96/106] Performing install step for 'luv-static'
[0/1] Install the project...
-- Install configuration: "RelWithDebInfo"
-- Installing: /home/maltimore/repos/neovim/.deps/usr/lib/libluv.a
-- Installing: /home/maltimore/repos/neovim/.deps/usr/include/luv/luv.h
-- Installing: /home/maltimore/repos/neovim/.deps/usr/include/luv/util.h
-- Installing: /home/maltimore/repos/neovim/.deps/usr/include/luv/lhandle.h
-- Installing: /home/maltimore/repos/neovim/.deps/usr/include/luv/lreq.h
[98/106] Generating usr/lib/luarocks/rocks-5.1/mpack
FAILED: usr/lib/luarocks/rocks-5.1/mpack /home/maltimore/repos/neovim/.deps/usr/lib/luarocks/rocks-5.1/mpack
cd /home/maltimore/repos/neovim/.deps && /home/maltimore/repos/neovim/.deps/usr/bin/luarocks build mpack 1.0.8-0 CC=/usr/bin/cc LD=/usr/bin/cc
Warning: Failed downloading. Attempting mirror at https://raw.githubusercontent.com/rocks-moonscript-org/moonrocks-mirror/master//mpack-1.0.8-0.rockspec
Warning: Failed downloading. Attempting mirror at https://luafr.org/luarocks//mpack-1.0.8-0.rockspec
Warning: Failed downloading. Attempting mirror at http://luarocks.logiceditor.com/rocks/mpack-1.0.8-0.rockspec

Error: Error fetching file: Failed downloading https://luarocks.org/mpack-1.0.8-0.rockspec -
failed downloading https://luarocks.org/mpack-1.0.8-0.rockspec
failed downloading https://raw.githubusercontent.com/rocks-moonscript-org/moonrocks-mirror/master//mpack-1.0.8-0.rockspec
failed downloading https://luafr.org/luarocks//mpack-1.0.8-0.rockspec
failed downloading http://luarocks.logiceditor.com/rocks/mpack-1.0.8-0.rockspec

ninja: build stopped: subcommand failed.
make: *** [Makefile:107: deps] Error 1

So I’m wondering what I"m doing wrong? When I try to manually download the file https://luarocks.org/mpack-1.0.8-0.rockspec, there’s no issue, both via the browser and via curl.

I’m on KDE Neon 20.04, which is basically Ubuntu 20.04. I have installed the build dependencies like advised on the neovim wiki (on github).