When you add facebook login to your wordpress.
First of all. you must create your facebook app in facebook developer
You must sign up and create an app.
after you have create an app.
If you are hosting with AD Region Company, please follow the steps.
Don’t forget to go back to your website control panel
login in >> Advanced >> Outgoing Connections
select “De-activate”
If you don’t do as above, you will not able to connect to facebook.