4xx errors could be caused by a malfunction on the Origin side or incorrect CDN-resource's settings.
Check the content availability on the Origin-source
Request the content from the origin-source and ensure that you get an HTTP 200 response code.
If you use IP Whitelist on the origin or use DDoS protection service, ensure that CDN-edges IPs are whitelisted. Use the API-request above to get the list of Public IP
curl -i -X GET https://api.gcorelabs.com/cdn/public-ip-list
Since we constantly update the Public IP list, we recommend you to run script for the regular whitelist updating. You can also use HTTP Request Header for the authentication on your origin. You may find out more about the Origin ACL here.
Check your CDN-resource's settings
- Ensure that the CDN resource is active. If you have created a new resource, wait until its configuration applied on CDN-edges. Usually, it takes 15 minutes.
- Ensure that the Origin can respond to the requests from CDN edges by chosen Origin Pull Protocol. You may learn more about this option from the article.
- Check the Change Host Header option. Make sure that the option is active, and the value is the same as the Origin Source or match with the host that you have set up on the Origin. You may find more information about Host Header here.
Go the Reports tab to track the amount of 4xx errors.
To receive more details about user’s requests to resources use the Raw logs option. It is a paid feature. The Raw log receiving setup flow and the description of logs’ fields are located here. If you want to activate this feature, contact your account manager or send a request to technical support (firstname.lastname@example.org).