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Check CDN operation
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Check CDN operation

If there are errors or slow download speeds of content via CDN, check:

Check balance⁠

  1. In control panel go to CDN → CDN resources.
  2. Look at the account balance in the upper right corner and the status of the CDN resource. If the balance is negative and the CDN resource is in status DOWNthen the CDN resource was shut down for non-payment.
  3. To enable a CDN resource, top up with the amount owed, then share.

Check CDN resource⁠

The check will show the status of the CDN resource, the correctness of the CNAME record and the availability of the file from the content source and CDN server.

  1. In control panel go to CDN → CDN resources. Check it out status in the CDN resource string. If the resource is in the status ERROR or hovering in one of the statuses, file a ticket.
  2. Open the file on the content source using a link of the form example.com/images/image.png. If the file doesn't load, the problem is on the side of your site.
  3. Open the file through the default domain using a link of the form *.selcdn.net/images/image.png. Default domain can be viewed in control panel: section CDN → CDN resources → resource page → tab General. If the file does not load, check Host header.
  4. Open the file through your personal domain using a link of the form cdn.example.com/images/image.png. Personal domain can be viewed in control panel: section CDN → CDN resources → resource page → tab General. If the file does not load, check if the file is correct resource record of the domain.

Check content loading speed⁠

The first time you access the content source, it takes longer to download the file than on subsequent accesses (when the file is distributed from the cache). If a VPN or proxy is enabled, this may slow down the download speed of content.

  1. Open the file on the content source and check the download speed, you can do this through the developer tools in your browser.
  2. Open the file on domain which is used to distribute content via CDN. The domains can be viewed in control panel: section CDN → CDN resources → resource page → tab General.
  3. Re-open the file on the domain with the CDN and check the download speed.
  4. Compare the download speed of the file from the source and from the CDN cache. If the download speed from CDN and the source is the same, CDN is working correctly. If the CDN download speed is slower, leave a diagnostic request.

Leave a request for diagnostics⁠

  1. Record the HTTP session demonstrating the CDN error in HAR file format. For more information about recording a HAR file for Edge, Firefox, or Chrome, see the instructions How to get a HAR file of the Google Admin Toolbox portal.

  2. Go to diagnostic page and take a screenshot of the metrics.

  3. On the diagnostics page, in the line Server follow the link to test the download speed. Perform the test and take a screenshot of the results.

  4. Create a ticket with a request for diagnostics. Specify in the ticket:

    • CDN resource name;
    • a link to a file on the domain that is used to distribute content via CDN;
    • HAR file that you created in step 1;
    • screenshots that you created in steps 2 and 3;
    • mass of requests with the problem and the location of users who have the problem.