Refresh token does not work in sample code for DropBox.

[surusaki8]

I am using the sample code for DropBox, but the refresh token does not work and always issues a redirect URL for issuing an access token.
Does anyone know a solution?

[surusaki8]

Thank you very much for your help. I can now make an API request after a few hours and it returns the value I expected. I think I have probably solved the problem.