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Why are the images not accessible by ShortPixel AI or Autoptimize?

This article refers to both ShortPixel Adaptive Image (SPAI) and Autoptimize (AO).

There are usually 
7 possible reasons why you find that an image isn’t delivered from the ShortPixel’s CDN, but from the original location (after a temporary redirect, HTTP code 302 or 307), which almost always means that our servers cannot access the images.

Please make sure you understand how the plugins work:

  1. The first and by far the most common reason is that the first time
    an image is first accessed
    (any new image size is considered a “new” image) it’s registered for processing by ShortPixel, but so that the client doesn’t have to wait a few seconds, the original image is immediately returned via an HTTP 307 redirect. After a few seconds, or minutes in extreme cases, the image hosted in the CDN should be displayed when the page refreshes. Please note that the time it takes for the image to become available often depends on your browser’s cache.
  2. In many cases, a firewall prevents ShortPixel’s servers from accessing the images on the original website. It can be one of your plugins, your hosting, or your CDN. The solution is to whitelist ShortPixel’s IPs, as described here.
  3. The files aren’t publicly accessible because they are on a website hosted on an intranet, the website is password protected, or there are defined rules on your .htaccess file (usually for anti-hotlinking). The solution is to have the website hosted publicly on the Internet, remove any password protection and make sure there are no .htaccess rules that may prevent ShortPixel’s API from accessing the images.
  4. Cloudflare or some other CDN providers may also be the cause; as part of their security measures, they may require human input, and since our servers aren’t human, they fail this check. The solution is to whitelist ShortPixel’s IPs, as described here.
  5. There is no more CDN traffic quota available in the account associated with the website where ShortPixel Adaptive Images or Autoptimize is installed. The solution is to purchase more CDN traffic.
  6. If there is enough CDN traffic in your account, the domain/website where you’re using SPAI or AO is probably not associated with your account. Please associate the domain to your account and the images should start being served by ShortPixel’s CDN shortly.
  7. If you are using an external CDN and not ShortPixel’s default one, and you have used up your credit, you may see 302 redirects. These redirects may be cached by your external CDN. So as soon as you add more credits to your account, you should clear your CDN cache to get rid of these redirects.

If none of these reasons apply, we recommend flushing the redirected images from our CDN cache following
these instructions and trying again.