`scripts/head.hackage update` is broken

The head.hackage website currently recommends the use of scripts/head.hackage.sh update instead of cabal new-update, since the latter is known to be buggy due to Cabal #5952. However, I am unable to actually use scripts/head.hackage update when I try it locally:

$ ./scripts/head.hackage.sh update
INFO: 'cabal' is recent enough and supports 'cabal new-update head.hackage'; you can try using that directly!

Warning: Caught exception during _mirrors lookup:user error (res_query(3)
failed)
Warning: No mirrors found for https://ghc.gitlab.haskell.org/head.hackage/
user error (https not supported)