Phoenix App CORS Configuration Issue with Deployment

Questions & Help Questions
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If anyone encounters the same issue in the future, here’s how I resolved it:

I moved the environment variable fetching logic to a helper module, which fixed the problem.

plug CORSPlug, origin: &MyAppWeb.Config.cors_origins/1

Here’s the helper module:

defmodule MyAppWeb.Config do
  def cors_origins, do: Application.get_env(:my_app, :cors_origins)
end

Note: Ensure you use the capture operator (&) when calling the function in the plug. Calling it without the capture operator will not work—I made this mistake and spent an entire day debugging it.

I hope this helps anyone facing a similar issue!