Unable to connect Discourse and WordPress

URL is https://discuss.guidery.com

Performance and Security are disabled for the “discuss” subdomain via a page rule.
SSL is set to “Full (Strict)”

The error message I am seeing is “cURL error 6: Could not resolve host: discuss.guidery.com” which is being reported by the WP Query Monitor plugin.

Issuing the same cURL command from my local machine works without issue.