Troubleshooting the 401 Error in Page Speed Tests

If you have run your site through a page speed tool such as GTmetrix, Google PageSpeed Insights, or a similar service, you may have noticed a request to /wp-json/optml/v1/optimizations returning a 401 status code with the message MISSING_AUTHORIZATION_HEADER. This guide explains what that error means, why it appears, and whether you need to take any action.

🔍 What Causes the 401 Error?

The /wp-json/optml/v1/optimizations endpoint is a protected REST API route used internally by the Optimole plugin. It requires a valid authorization header before it will process any request.

When a page speed tool scans your site, it sends unauthenticated HTTP requests to every URL it discovers — including this endpoint. Because the tool does not supply the required authorization header, the endpoint deliberately returns a 401 MISSING_AUTHORIZATION_HEADER response. This is the correct, expected behavior: the endpoint is rejecting an unauthorized request exactly as it is designed to do.

📝 Note: This 401 response is a security feature, not a bug. It prevents unauthorized third parties from accessing or manipulating Optimole's internal optimization process.

⚡ Does This Affect My Site's Performance?

No. The 401 error you see in page speed reports has no impact on how Optimole works for your real visitors.

When a visitor loads a page on your site, Optimole handles image optimization through its own internal, authorized process. The plugin never relies on unauthenticated calls to this endpoint during normal operation. Real users browsing your site never trigger or encounter this error.

The 401 response that appears in your speed test report is purely a result of the scanning tool probing an endpoint it has no credentials for. Your images are still being optimized and delivered correctly to every visitor.

💡 Tip: Page speed tools sometimes flag non-200 responses in their request waterfall. A 401 on a protected internal endpoint does not reduce your performance score in any meaningful way and can safely be ignored.

✅ How to Verify It's Not an Issue

You do not need to make any configuration changes. The following steps can help you confirm that Optimole is working correctly on your site despite what the speed test report shows.

1. Visit any page on your site in a regular browser window (not logged in to WordPress).
2. Open your browser's developer tools and switch to the Network tab.
3. Reload the page and look at the images being loaded.
4. Confirm that image URLs are being served through Optimole's CDN (the URLs will contain i.optimole.com or your custom CDN domain).
5. If images are loading through Optimole, the plugin is functioning correctly. The 401 in the speed test report is not affecting image delivery.

📝 Note: If you use Cloudflare or another proxy/CDN in front of your site, the behavior is the same. Optimole's internal endpoint still requires authorization and will correctly return 401 to any unauthenticated scanner, regardless of your network setup.

If you still need help, feel free to contact our support team.