Deploy to Render.com fails. `undefined function config_env/0`

Here’s the build.sh file:

#!/usr/bin/env bash
# exit on error
set -o errexit

# Initial setup
mix deps.get --only prod
MIX_ENV=prod mix compile

MIX_ENV=prod mix assets.deploy
MIX_ENV=prod mix phx.gen.release

# Build the release and overwrite the existing release directory
MIX_ENV=prod mix release --overwrite

I’m able to do a production build locally.

However it doesn’t build on Render!