Put something like this in your settings
#Authentication backends
AUTHENTICATION_BACKENDS = (
'django.contrib.auth.backends.ModelBackend',
)
or if you are using userena for your accounts
#Authentication backends
AUTHENTICATION_BACKENDS = (
'userena.backends.UserenaAuthenticationBackend',
'guardian.backends.ObjectPermissionBackend',
'django.contrib.auth.backends.ModelBackend',
)