I suspect the issue might be config based, how different are your dev.exs and prod.exs config files (if you organise them this way), when you say “production” what does that involve for you? Are you building an RPM or something similar?
The issue could lie at many points along the chain so some more info would be very helpful in order for us to help you
EDIT: The best way to diagnose this is highlight all the things that are different between production and dev.