Unable to set the environment variable for the tracker

Hi, In my endpoints.yml, I had raw password value. As I want to go to production, I want to replace this terms with environment variables for having a bit of security. Here is my endpoints.yml file:

tracker_store:
  type: SQL
  dialect: "postgresql"
  port: 5432
  db: ${DB_DATABASE}
  username: ${DB_USER}
  password: ${DB_PASSWORD}
  url: '127.0.0.1'

Actually when I executed I have a valueError:

ValueError: Error when trying to expand the environment variables in ‘${DB_DATABASE}’. Please make sure to also set these environment variables: ‘[’${DB_DATABASE}’]’

I use rasa version: 1.4.3 and I don’t have rasa-x installed.My OS is Linux.

Is someone encounter an error of a kind. Will be pleased to get a help.

Thanks in advance.

Same problem. Still nothing?