Setting up OAuth 2.0 - What does this error mean: Invalid scope

This article is part of the article serie Setting up OAuth 2.0 - Introduction

During authentication this error occurs:

"error": "invalid_scope"

To resolve this error please take note that:

- It is mandatory to add the openid scope when you have added the twf.user. 
- Make use of spaces between each scope in order to receive the correct "+" sign in your url.

Additional information concerning your scopes:

The twf.organisationUser scope is mandatory in order to login and please notice that you also add the offline_access scope for receiving your refresh token using the authorization code flow.

Example:
scope= openid+twf.organisationUser+twf.user+twf.organisation+offline_access