Need help deploying to Red Hat Enterprise Linux (RHEL)

I definitively have elixir and erlang installed. Running mix -v on the server gives me:

Erlang/OTP 19 [erts-8.2] [source-fbd2db2] [64-bit] [smp:4:4] [async-threads:10] [hipe] [kernel-poll:false]

Mix 1.4.0

I’ll read the link and see if I missed anything.

*edit
I had to build elixir from source to get a recent version, but it works when I’m ssh’d in.