Debugging of Flask Web App (Emails not sent out)

I have a Python/Flask app deployed on an Ubuntu/Apache server. I sort of have an issue with the app reading the config.env files properly and as such the app cannot access environment details e.g Database URI and Email SMTP settings.
I would like you to debug this and enable the email function to work so that if a user registers there is a confirmation email sent to the user.

These have all been coded but the issue is the app cannot read the environment variables as I earlier suggested.