Hi Nilesh,

Try with below steps and let us know if this helps.

1.
Social Login with Salesforce Communities Yuji Yasuno Sales Support Engineer /yuji.yasuno @yuji_yasuno in/yujiyasuno
2. Agenda • Values • The Big Picture of Social Login with Communities • Setup • Setup for Mobile
3. Identity Provider Identity Provider gives power to communities letting users login with SNS Account
4. Values • Social Login can help the registration, username and password problem, and provide the useful profile data. • Social Login delivers value both to consumers and companies. ‣ ‣ ✴ Makes registering and logging into a site much easier. Grants permission-based access to profile data that can be used personalize the users’ experience. These are a quotation from The Value of Social Login(http://www1.janrain.com/rs/janrain/images/ Industry-Research-Value-of-Social-Login-2013.pdf).
5. The big picture - use case Remarks This point actually has a few HTTPS requests but I only put one arrow so that easy to understand the use case. 1. Try to login to Salesforce with using Facebook ID. 2. OAuth Authorization. 3.Request user’s profile data. 5. Return the communities’ page 4. Return the user profile data
6. The big picture - architecture salesforce facebook Request a profile data User Return a profile data Identity Provider gives profile data to registration handler(Apex) The registration handler manages the User object records. (required to write the code for deciding how to create or update a user)
7. Setup - step1 • Create an Auth. Provider Setting > Administrator > Security Controls > Auth. Providers Don’t forget to set Registration Handler(you can create automatically by clicking link).
8. Setup - step2 • Enable Options of Auth. Provider login in Communities’ Login Page setting. Setting > Build > Customize > Communities > Manage Communities >(select your a community) > Login Page Enable the option that you made from Auth. Provider
9. Setup for Mobile - step1 • Same as the previous pages’ setup instructions of step1 and step2. • Create a Connected Apps. Mobile SDK needs this information.
10. Setup for Mobile - step2 • Change login domain of your mobile application. Change Login Host to Custom Host and set the value as Communities domain. *Don’t forget put / and community name after the domain.
11. Finally, You can log in using Facebook account!
12. Remarks If you want to change the behavior of login, i.e. changing how to update user data referring SNS profile and decide how to create a user for registration, please change the registration handler that is automatically created. <http://www.salesforce.com/us/developer/docs/apexcode/Content/apex_auth_plugin.htm>

Hope this helps.

Kindly mark this as solved if the information was helpful so that it gets removed from the unanswered queue which results in helping others who are encountering a similar issue.

Thanks,
Nagendra