If you are receiving the following 403 errors: "message": "The used authentication method is not allowed on this route." "message": "This route can only be accessed by anonymous users." Then keep reading for how to resolve them.   Attempting to log in to a Drupal site using REST API and I had to battle a few head winds along the way.  What is worse, they were self imposed!   Attempting to authenticate I was initially using the following to login in a user method: post url:...

If you are like me you probably have searched for clues to and found little... particularly when confronted by the errors as you unravel how this works.  Okay a slight exaggeration, there are snipets of info that people have solved this annoying issue in  making comments work in Drupal 8 REST services. The lack of collective information in resolving issues has meant hours of debugging and working through core code to understand what is actually happening.  If you want to...