Both ShortPixel Adaptive Images (SPAI) and Autoptimize‘s Image Optimization need to access your images in order to optimize them and serve them from our CDN.
If you have in place a hotlinking prevention feature then it is possible that all ShortPixel’s servers can see is a replacement image with a hotlinking warning message. For example:
This is how the process works simplified:
- Your page has an image.
- Knowing that both SPAI and Autoptimize work on the fly, when a user visits your site, they tell our servers to access the image to optimize.
- When our servers try to access the image, the hotlinking prevention feature serves the hotlinking placeholder image instead of the original correct image.
- Our servers optimize the wrong image.
- Our CDN serves the wrong image to all your users. 🙁
To solve this, you have two options:
- Completely disable the hotlinking prevention feature. You should check your plugins, hosting and/or your CDN for this. If you are using Plesk, please deactivate its hot-linking protection option as described in this article.
- Allow our servers to access the images. For this, please whitelist our IPs on all your security plugins, hosting and/or CDN. IPs to be whitelisted – ShortPixel Knowledge Base
Either way, after the issue is resolved from your side, make sure you flush ShortPixel’s CDN cache.