I am using the latest CiviCRM 5.18.4 and Backdrop 1.15.x-dev all up to date.
I am new to CiviCRM, but have used Drupal 6,7 and 8 over the years. I have been following the excellent documentation, I am sure I have done everything correctly to create a Contribution Page with a profile to allow a visitor to create a CiviCRM Account in the 'host' Group I have created, because when I add a user he/she appears with all the correct data from the profile and in the correct Group, but the user is not added as a Backdrop User.
In the Profile I have 'Drupal User Registration' and 'View/Edit Drupal User Account' checked, so it should work. I have looked all over this forum, and searched extensively on the internet, but cannot find an answer.
I have enabled debugging but there are no errors in the CiviCRM or Backdrop logs. I can add a new user as a visitor in Backdrop, I have tested that. Works fine.
Any help much appreciated. Is it something to do with the Backdrop Permissions? IF so what should those be?