Getting 409 error when trying to list folders when using refresh token

adamatronix,

Even though it appears as though you are indeed passing a refresh token to the request in your third code snippet example, the request is defaulting to "Basic auth" because it is not recognizing the value of the refresh token — meaning, this is most likely an empty value. A malformed or invalid refresh token would throw a different error.

I recommend double-checking that the refresh token is being correctly pulled in from the env file into the configuration of the new Dropbox client instance.

Manually creating an access token, using the refresh token, as you mentioned in your latest post could be an alternative as well.