I’m trying to connect a Standard plan customer (@andrec) to their WordPress. I’ve copy-pasted the URL, and used the API key to remotely change settings, so I’m sure those are both correct.
I then disabled all plugins except wp-discourse and still no joy.
The only system settings changed on the Discourse side is the SSO key, which is the same in Discourse and WordPress, and shouldn’t matter since SSO isn’t enabled yet anyway.
Could you try generating an API Key on Discourse for @andrec and using that in place of the All Users API key?
If that doesn’t fix anything there may be an issue with the HTTPS configuration of the WordPress site. You can check for that by installing this plugin and running the test with the Paypal API endpoint.
If the WordPress site was installed with the Digital Ocean 1 click WordPress install you may need to install the php-curl extension.