[Plugin: Facebook Comments] How to Allow Facebook Access to Protected Content

I am using Facebook Comments plugin on password protected pages. I have recently found that when a new post is created I get the error ‘facebook comments {page} is unreachable’ and when I debug using Facebook’s debug tool no ID is found. However FB Namespace, meta tag and js are all inserted correctly and work fine on all non protected pages.

When I disable the password protection and refresh the page everything works fine and after being loaded correctly that once it seems to be fine when I re enable the password protection also.

So I guess Facebook needs to be able to access the page the first time to authenticate the page.

Is there a way I can allow Facebook to access the page initially. For example in my verification function I could add:

if( can_user_view_content() || is_request_from_facebook() ){
//echo content and comments

Does Facebook send a useragent string I could use or is there a better way than testing for user agent?

Thanks

https://www.ads-software.com/extend/plugins/facebook-comments-plugin/