Assume that the Alibaba Cloud CDN domain is www.a.com.
Check whether the used domain is connected to Alibaba Cloud CDN.
Type cmd and press Enter to perform a Ping test. Check whether the CNAME with the kunlun*.com suffix exists. If yes, the domain name is successfully resolved to an Alibaba Cloud CDN node. If the IP address in the Ping result is still the IP address of the origin site server mapped to the domain name, access to the origin site is abnormal. In this case, troubleshoot the origin site service.
Check whether access to the origin site is normal
If you determine that the domain name is successfully resolved to an Alibaba Cloud CDN node in the previous step, type a URL under the domain in the address bar of a browser to check the effect of Alibaba Cloud CDN based access. Add the
220.127.116.11 www.a.comentry to the hosts file and save the file, clear the cache of the browser, restart the browser, and type the URL again. At this time, the website content must be served from the origin site. If the website cannot be opened normally, access to the origin site is abnormal. In this case, troubleshoot the origin site. If access to the origin site is normal but access using the Alibaba Cloud CDN domain is abnormal, go to the next step.
Check whether the Alibaba Cloud CDN configuration is correct.
Check the configuration of the www.a.com domain and check the correctness of CNAME:
**Note:** The CNAME generated from the www.a.com domain on the platform can be used only by www.a.com. The CNAME cannot be used by other domains such as img.a.com.
Check the origin site configuration.
Check whether the configured origin site is the origin site server mapped to the domain name. If not, change the IP address of the configured origin site to the IP address of the origin site server.
Check the security policy of the origin site.
The Alibaba Cloud CDN configuration is proper if the check procedure from Step 1 to Step 4 shows no configuration errors. Then check whether a security policy (such as a firewall or dongle) is configured for the origin site. If yes, check whether there are interception records on the two IP address segments: 18.104.22.168/25 and 22.214.171.124/25. If yes, add the IP address segments to a whitelist.
If the problem persists, contact Alibaba Cloud After-Sales Technical Support.