Getting error "No access: User was a portal user" Social Log-In when logging with Facebook SSO

Question

I have been following this trailhead to allow users login in a community using facebook:

https://trailhead.salesforce.com/en/modules/identity_external/units/identity_external_social

I dont want them to register, I only need they will be able to login. To get this I have modified the SF automatic handler.

global class SimpleFacebookRegistrationHandler implements Auth.RegistrationHandler{  

    global User createUser(Id portalId, Auth.UserData data){
        List<User> listUsers = [SELECT Id FROM User WHERE UserName = :data.email AND Profile.Name = :ProfileHelper.COMMUNITY_PROFILE LIMIT 1];
        if(listUsers.isEmpty()){
            return null;
        }else{
            return listUsers[0];
        }
    }

    global void updateUser(Id userId, Id portalId, Auth.UserData data){}

}

So then I go to the link provided by SF in the corresponding "Auth Providers" section, log in with FB and get the next error: "No access: User was a portal user"

What am I missing? Well, it is pretty obvious that the user was a portal user but if I can login using the "normal login" why I get this error being logged using facebook?

Answer 1

To others with same problem:

I just had to add

?community=COMMUNITY_URL_ENCODED 

to the link I was using (https://test.salesforce.com/services/auth/sso/.../Facebook) so at the end it worked visiting:

https://test.salesforce.com/services/auth/sso/.../Facebook?community=https%3A%2F%2examplecommunity.force.com