ejabberd Won't Start with mod_prometheus Installed

[rhclayto]

ejabberd/stable,now 24.12-3 amd64 installed from Debian trixie repository.

Installed mod_prometheus with ejabberdctl module_install mod_prometheus. On install, there were errors like:

I'll download "quantile_estimator" using git because I can't use Mix to fetch from hex.pm:

ejabberd won't start with mod_prometheus installed. Here are my log messages:

Dec 31 17:28:48 comms sh[1427541]: I'll download "quantile_estimator" using git because I can't use Mix to fetch from hex.pm:
Dec 31 17:28:48 comms sh[1427541]: ** (Mix) The task "hex.package" could not be found
Dec 31 17:28:48 comms sh[1427541]: Note no mix.exs was found in the current directory
Dec 31 17:28:48 comms sh[1427541]: I'll download "prometheus" using git because I can't use Mix to fetch from hex.pm:
Dec 31 17:28:48 comms sh[1427541]: ** (Mix) The task "hex.package" could not be found
Dec 31 17:28:48 comms sh[1427541]: Note no mix.exs was found in the current directory
Dec 31 17:28:49 comms sh[1427541]: 2025-12-31 17:28:49.454018-07:00 [critical] Failed to start Erlang application 'ddskerl': no such file or directory: ddskerl.app. This usually means that ejabberd or Erlang was compiled/installed incorrectly.
Dec 31 17:28:49 comms systemd[1]: ejabberd.service: Main process exited, code=exited, status=1/FAILURE
Dec 31 17:28:49 comms systemd[1]: ejabberd.service: Failed with result 'exit-code'.

I have installed the full erlang & erlang-dev packages from Debian, also elixir:

erlang/stable,now 1:27.3.4.1+dfsg-1 all [installed]
erlang-dev/stable,now 1:27.3.4.1+dfsg-1 amd64 [installed]
elixir/stable,now 1.18.3.dfsg-1 amd64 [installed]

Any ideas or clues here?