It seems bug of facebook-sso.
Read this :
I've been having this issue too.
If we have a Rails system, we want to use that system's user database, is there anyway to do SSO. also be able to get topic or post data through API of NODEBB, just wondering what's the unique key or API I will need to use.
Anybody has experience? thanks.
There are quite a few SSO plugins, but since you have your own "rails" system, it would probably have to be a custom plugin.
As psychobunny suggests with the referenced links, you cant elaborate your own SSO plugin to gain acces from nodeBB to the user stored on your own database, making your Rails system to act as the SSO provider.
The other link is the write API nodebb provides. You would have to install this plugin in order to have it working.