Maybe a daft question, but here’s what I see on a private only forum:
The 419 error:
HTTP Error 419 (Page Expired) is a non-standard HTTP status code primarily used by the Laravel PHP framework to indicate that a Cross-Site Request Forgery (CSRF) token validation has failed or that your session has expired
My WP instance is connected via DiscourseConnect as the provider to this Discourse instance, but the domains are different. Can I assume that is the cause of this error?
Embedding comments from a private site
For private Discourse instances, if Discourse is on a subdomain of the blog’s domain, comments will be displayed for users who are logged into Discourse. Users who are not logged into Discourse will see a ‘refused to connect’ message. If Discourse and the blog are on completely separate domains, no comments will be displayed for private forums.