CDN:White screen error when accessing a website through CDN

Problem description

Customers report a blank page when they access a webpage that is accelerated by Content Delivery Network (CDN). This prevents the page from loading correctly.

Troubleshooting

1. A white screen error is usually caused by an issue with loading static resources, such as JavaScript or CSS files. To start, compare the network requests from accessing the origin server directly with the requests from accessing the server through CDN.

   1. Bind the domain name to the origin IP address in your local hosts file. Access the origin server directly and save the network requests as a HAR file.

   2. Access the same page through CDN and save the network requests as a HAR file.

   3. Compare the two HAR files to identify the resource with the abnormal response.

2. If you confirm that the issue is caused by a resource cached by CDN, refresh the cache for the affected resource.

3. Check the CDN console for features that might affect resource requests, such as URL rewrite and following 302 redirects for origin fetch.

Solutions

1. If you have configured the feature to follow 302 redirects for origin fetch, disable the feature. For more information, see Follow 301/302 redirects for origin fetch.

2. Use the Refresh Cache API to refresh the cache for the affected page URL. Set the Force parameter to true.

   Note

   You must use the Refresh Cache API to submit a refresh task. Using directory refresh or regex-based refresh in the console only marks the cached content as expired. This means that if the file on the origin server has not changed but its response headers have, a refresh from the console might still serve the old content. An API call with the Force parameter set to true ensures the content is purged from CDN nodes. For more information, see CDN cache refresh mechanism.