ExCrowdin.Config.access_token

You're seeing just the function access_token, go back to ExCrowdin.Config module for more information.

In config.exs, use a string, a function or a tuple:

config :ex_crowdin, access_token: System.get_env("CROWDIN_ACCESS_TOKEN")

or:

config :ex_crowdin, access_token: {:system, "CROWDIN_ACCESS_TOKEN"}

or:

config :ex_crowdin, access_token: {MyApp.Config, :crowdin_access_token, []}