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Check CDN Performance

If you encounter errors or slow content loading via CDN, check the following:

Check balance

  1. In the Control Panel, in the top menu, click Products and select CDN.
  2. Check 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 the INACTIVE status, the CDN resource was disabled for non-payment.
  3. To enable the CDN resource, top up the balance covering the debt amount, and then enable the CDN resource.

Check CDN resource

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

  1. In the Control Panel, in the top menu, click Products and select CDN.

  2. In the CDN resource row, check the status. If the resource is in the ERROR status or is stuck in one of the statuses, create a ticket.

  3. Open the file on the content origin using a link formatted like example.com/images/image.png. If the file does not load, the problem is on your website's side.

  4. Open the file via the default domain using a link formatted like *.selcdn.net/images/image.png. The default domain can be viewed in the Control Panel: in the top menu, click Products → CDN → CDN resource row. If the file does not load, check the Host header.

  5. Open the file via a custom domain using a link formatted like cdn.example.com/images/image.png. The custom domain can be viewed in the Control Panel: in the top menu, click Products → CDN → CDN resource row. If the file does not load, check whether the domain's CNAME record is correct.

Check content download speed

When you access content from the origin for the first time, loading the file takes longer than during subsequent requests, when the file is served from the cache.

  1. Ensure that you have disabled VPN or proxy on the device you are using for testing — these can slow down the download speed.

  2. Check the download speed from the origin:

    2.1. Open the file on the content origin.

    2.2. Check the file download speed: open developer tools in your browser → the Network tab → check the value in the Time column.

  3. Load the file into the CDN cache: open the file on the domain used for content delivery via CDN. Domains can be viewed in the Control Panel: in the top menu, click Products → CDN → CDN resource page → the General tab.

  4. Check the download speed from the CDN cache:

    4.1. Open the same file on the CDN domain that you opened in step 3.

    4.2. Check the file download speed: open developer tools in your browser → the Network tab → check the value in the Time column.

  5. Compare the file download speed from the origin and from the CDN cache. If the download speed via CDN is greater than or equal to the download speed from the origin, CDN is working properly. If the download speed via CDN is lower, submit a diagnostics request.

Request diagnostics

  1. Record an 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 How to get a HAR file guide on the Google Admin Toolbox portal.

  2. Create a ticket requesting diagnostics. In the ticket, specify:

    • CDN resource name;
    • link to the file on the domain used for content delivery via CDN;
    • HAR file that you created in step 1;
    • scale of the issue and the location of users experiencing it.