[Answer]-Django social auth in existing project

Haven’t got much experience working with SocialAuth, it seems here you are trying to create a new user with the same email for which the User object already exists.

I recently used “AllAuth”, this seems to have a much wider utility set, is easy to integrate and support for the same is still provided. You could integrate and use the same using the following links:

• https://github.com/pennersr/django-allauth
• http://www.sarahhagstrom.com/2013/09/the-missing-django-allauth-tutorial/

Hope this helps!