Setup Cross-Origin Resource Sharing (CORS)

Documentation Self-Hosting
3

I have added the DISCOURSE_ENABLE_CORS: "true" to the env section of my site’s app.yml file.
I then rebuilt the app.
I then went to the cors_origins section and added the full URL of a site I’m trying to get an interaction working with and it’s still not working.
I’ve created a page to serve information when the main site is offline.
I put this js in the page to check the main site and redirect to it once it’s back up but it doesn’t seem to be working.
Here’s the code:

    <script>
        function checkSiteStatus() {
            fetch('https://discourse.technospider.com', {
                method: 'HEAD',
                mode: 'cors', // Use CORS to get status code
                cache: 'no-store' // Avoid caching
            })
            .then(response => {
                console.log('Site check: Status', response.status);
                if (response.ok) { // 200-299 status codes
                    console.log('Site is up, redirecting to Discourse');
                    window.location.replace('https://discourse.technospider.com');
                } else {
                    console.log('Site is still down (status: ' + response.status + '), retrying in 20 seconds');
                    setTimeout(checkSiteStatus, 20000);
                }
            })
            .catch(error => {
                console.log('Site check: Error (likely down or CORS issue):', error.message);
                setTimeout(checkSiteStatus, 20000);
            });
        }
            
        // Start checking immediately
        checkSiteStatus();
    </script>

And this is the console error:

[Error] Origin https://www.technospider.com is not allowed by Access-Control-Allow-Origin. Status code: 200
[Error] Fetch API cannot load https://discourse.technospider.com/ due to access control checks.
[Error] Failed to load resource: Origin https://www.technospider.com is not allowed by Access-Control-Allow-Origin. Status code: 200 (discourse.technospider.com, line 0)
[Log] Site check: Error (likely down or CORS issue): – "Load failed" (berightback, line 78)

If anyone has any insights I’d love to know about them. Grok and I are at a loss.