Install at "pleroma mix deps.get" fails

Alpine linux (4.19.80-0-vanilla) fresh install Ipv6 only connection (with dns/nat64)

I can resolve repo.hex.pm (it has ipv6 address) and wget/curl the file.

/opt/pleroma# sudo -Hu pleroma mix deps.get
!!! RUNNING IN LOCALHOST DEV MODE! !!!
FEDERATION WON'T WORK UNTIL YOU CONFIGURE A dev.secret.exs
Could not find Hex, which is needed to build dependency :phoenix
Shall I install Hex? (if running non-interactively, use "mix local.hex --force") [Yn]
** (Mix) httpc request failed with: {:failed_connect, [{:to_address, {'repo.hex.pm', 443}}, {:inet, [:inet], :nxdomain}]}

Could not install Hex because Mix could not download metadata at https://repo.hex.pm/installs/hex-1.x.csv.