Title: Not compatible with WP-Optimize Cache Preloading
Last modified: May 5, 2025

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# Not compatible with WP-Optimize Cache Preloading

 *  Resolved [mathijsen](https://wordpress.org/support/users/mathijsen/)
 * (@mathijsen)
 * [1 year ago](https://wordpress.org/support/topic/not-compatible-with-wp-optimize-cache-preloading/)
 * I’m using WP External Links and the WP-Optimize plugin for server-side caching.
   This plugin has a “cache preloading” option, which triggers WP-Optimize to cache
   the site by visiting pages to preload them (so that they are ready the first 
   time a human visitor wants them).
 * Whenever I visit such a site cached by “cache preloading”, all the things that
   WP External Links is supposed to add to an external link (CSS classes, FontAwesome
   symbol, rel tags…) are not there in the sites HTML source code. It’s like I had
   never used WP External Links in the first place. It seems like the action that
   WP External Links usually performs on external links before the site is delivered
   to the client is somehow supressed or not triggered when WP-Optimize is visiting
   the site for cache preloading.

Viewing 5 replies - 1 through 5 (of 5 total)

 *  Plugin Author [Alexandru Tapuleasa](https://wordpress.org/support/users/talextech/)
 * (@talextech)
 * [1 year ago](https://wordpress.org/support/topic/not-compatible-with-wp-optimize-cache-preloading/#post-18451491)
 * Sorry to hear about the issue. I have added it to our ToDO list to check but 
   I have a feeling it’s related to the output buffering we use to update the page
   HTML and it might not be fixable 🙁
 *  Thread Starter [mathijsen](https://wordpress.org/support/users/mathijsen/)
 * (@mathijsen)
 * [1 year ago](https://wordpress.org/support/topic/not-compatible-with-wp-optimize-cache-preloading/#post-18451502)
 * Thanks for the quick reply. Do you have any suggestion for a caching plugin offering
   preloading where this problem doesn’t occur or are you afraid that this is more
   like a fundamental problem “WP External Links vs. preloading”?
 *  Plugin Author [Alexandru Tapuleasa](https://wordpress.org/support/users/talextech/)
 * (@talextech)
 * [1 year ago](https://wordpress.org/support/topic/not-compatible-with-wp-optimize-cache-preloading/#post-18452833)
 * I don’t have any suggestions. I will have to look into it first, but it would
   depend on how the preloading is performed I guess so you could try some others.
 *  Thread Starter [mathijsen](https://wordpress.org/support/users/mathijsen/)
 * (@mathijsen)
 * [1 year ago](https://wordpress.org/support/topic/not-compatible-with-wp-optimize-cache-preloading/#post-18459159)
 * The Issue is has been resolved. The problem seemed to be on the side of WP Optimize
   since users in their support forum also mentioned similar conflicts with other
   plugins. WP Optimize released an update, the release note saying “FIX: Cache –
   Compatibility issue with other plugins due to late start of output buffering”
 * Now everything works fine again.
    -  This reply was modified 1 year ago by [mathijsen](https://wordpress.org/support/users/mathijsen/).
 *  Plugin Author [Alexandru Tapuleasa](https://wordpress.org/support/users/talextech/)
 * (@talextech)
 * [1 year ago](https://wordpress.org/support/topic/not-compatible-with-wp-optimize-cache-preloading/#post-18459365)
 * Great! So it was output buffering as I suspected. I’m happy to hear they fixed
   it. Thanks for letting me know 🙂

Viewing 5 replies - 1 through 5 (of 5 total)

The topic ‘Not compatible with WP-Optimize Cache Preloading’ is closed to new replies.

 * ![](https://ps.w.org/wp-external-links/assets/icon-256x256.png?rev=2103983)
 * [External Links - nofollow, noopener & new window](https://wordpress.org/plugins/wp-external-links/)
 * [Frequently Asked Questions](https://wordpress.org/plugins/wp-external-links/#faq)
 * [Support Threads](https://wordpress.org/support/plugin/wp-external-links/)
 * [Active Topics](https://wordpress.org/support/plugin/wp-external-links/active/)
 * [Unresolved Topics](https://wordpress.org/support/plugin/wp-external-links/unresolved/)
 * [Reviews](https://wordpress.org/support/plugin/wp-external-links/reviews/)

## Tags

 * [cache](https://wordpress.org/support/topic-tag/cache/)
 * [caching](https://wordpress.org/support/topic-tag/caching/)
 * [external links](https://wordpress.org/support/topic-tag/external-links/)

 * 5 replies
 * 2 participants
 * Last reply from: [Alexandru Tapuleasa](https://wordpress.org/support/users/talextech/)
 * Last activity: [1 year ago](https://wordpress.org/support/topic/not-compatible-with-wp-optimize-cache-preloading/#post-18459365)
 * Status: resolved