Problem linking Discourse forum to WP Discourse

Hi folks. I too, am having issues connecting Wordpress (5.7.1) to Discourse (2.7.0.beta7).

I’ve installed the WP_Discourse plugin on another Wordpress site to hook into my Discourse forum. For some reason it refuses to connect even though the API is correct and set to all users as well as the admin username properly set.

The plugin does pull in the name and URL of the forum in other parts of it but it still says: " **You are not connected to Discourse. If you are setting up the plugin, this notice should go away after completing the form on this page.*"

I also noticed since upgrading to the latest version of Discourse (I was a couple versions behind), on another WP site the plugin is no longer connected and when I try to reconnect it has the same issues above and is no longer connected.

I deactivated all WP plugins except for Discourse to see if it solved the issue, no go. Also checked security settings in Discourse to make sure I hadn’t inadvertently blocked all crawlers, etc. Not the issue.

I reissued Global APIs just in case. Natch. I also set up a global API just for my admin username and used that key, still natch.

Changed from my username to system as username, still no go.

Not sure what else I can do – how can I debug this further? Also, could it be a firewall issue? What ports are used?

Thanks,
Ray

P.S. I did recently change domains on the Discourse instance and followed the directions here. Everything else seems to be working fine.

Only other change is I recently updated Discourse from a couple versions behind to the latest.