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Why QUIC.cloud Can't Connect to Your WordPress REST API and How to Fix It

15 threads Sep 22, 2025 Plugin → Litespeed cache

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The Problem: QUIC.cloud Integration Fails with REST API Errors

A common issue for users of the LiteSpeed Cache plugin is encountering an error that prevents integration with the QUIC.cloud CDN and optimization service. The error message typically states: "QUIC.cloud’s access to your WP REST API seems to be blocked" or "QUIC.cloud service nodes cannot reach your WP REST endpoints."

This problem manifests as a failure to generate Critical CSS (CCSS) or Unique CSS (UCSS), and the QUIC.cloud Online Services panel may show that no cloud services are in use. A key symptom is that a test request to the REST endpoint, like https://yourdomain.com/?rest_route=/litespeed/v3/ping, returns a 404 error instead of the expected successful response.

Why Does This Happen?

This blockage is almost never due to a bug in the LiteSpeed Cache plugin itself. Instead, it is a configuration or conflict issue that prevents external QUIC.cloud servers from communicating with your WordPress site's backend. Based on community reports, the most frequent causes are:

  • Firewall Restrictions: A server-level firewall (e.g., ConfigServer Security & Firewall - cSF) or a security plugin (e.g., Wordfence) may be blocking the IP ranges of QUIC.cloud's service nodes.
  • .htaccess Misconfiguration: Rewrite rules in your .htaccess file might be interfering with or blocking access to the wp-json REST API endpoints.
  • Cloudflare or Other Proxies: While Cloudflare can work with QUIC.cloud, its Security or WAF settings might be blocking the API calls. Simply bypassing Cloudflare DNS may not be sufficient if specific page rules or security settings are active.
  • Permalink Structure: A corrupted or un-refreshed permalink structure can cause REST API paths to fail.

How to Troubleshoot and Fix the Connection

Here are the most effective steps to resolve this problem, starting with the most common solution.

1. Allow QUIC.cloud IPs in Your Firewall

The QUIC.cloud team maintains a list of IP addresses that their service nodes use. These IPs must be allowlisted in any firewall that protects your server.

  1. Find the current list of QUIC.cloud IPs. You can often find this by contacting your hosting provider or searching for official documentation.
  2. Work with your hosting provider to add these IPs to the allowlist in your server's firewall (e.g., cSF) and any security plugins you have active.

2. Check and Modify Your .htaccess File

Incorrect rules in your .htaccess file can block API access. You need to ensure that requests to the LiteSpeed REST API endpoints are explicitly allowed. Add the following rules to the top of your .htaccess file, before any other rewrite rules:

# Allow LiteSpeed/QUIC.cloud API callbacks
RewriteEngine On
RewriteCond %{REQUEST_URI} ^/wp-json/litespeed/ [NC]
RewriteRule .* - [L]

# Also allow the rest_route form used by QUIC
RewriteEngine On
RewriteCond %{QUERY_STRING} (^|&)rest_route=/litespeed/ [NC]
RewriteRule .* - [L]

3. Configure Cloudflare Correctly

If you use Cloudflare:

  1. Ensure the QUIC.cloud IP list is added to your Cloudflare WAF allowlist.
  2. Create a Page Rule for your domain with the pattern *example.com/wp-json/litespeed/* and set the action to Cache Level: Bypass and Security Level: Essentially Off. This prevents Cloudflare from blocking these specific requests.

4. Re-save Your Permalinks

Sometimes, simply refreshing your WordPress site's permalink structure can re-establish the correct REST API routes.

  1. In your WordPress admin dashboard, navigate to Settings > Permalinks.
  2. Without making any changes, click the "Save Changes" button.

5. Test the Connection

After making these changes, test the connection again. Visit the following URL in your browser, replacing yourdomain.com with your actual domain:

https://yourdomain.com/?rest_route=/litespeed/v3/ping

A successful response will show a simple "ping" message. If this works, the QUIC.cloud integration should now function correctly.

By methodically working through these configuration issues, you can restore the connection between QUIC.cloud and your WordPress site, allowing CSS optimization and other services to work as intended.

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