Title: Fatal Output Buffer Error
Last modified: August 7, 2026

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# Fatal Output Buffer Error

 *  [musa70](https://wordpress.org/support/users/musa70/)
 * (@musa70)
 * [5 days, 19 hours ago](https://wordpress.org/support/topic/fatal-output-buffer-error/)
 *  I sell flipbooks in my Woocommerce shop which I prepare with Real3DFlipbook 
   plugin. I installed and activated your plugin a few weeks ago to speed up page
   load time. And unfortunately my site started breaking in this time period with
   FATAL OUTPUT BUFFERING error on server side and net::ERR_HTTP2_PROTOCOL_ERROR
   on frontend side. I approximately tried all the combinations deactivating and
   activating all the other plugins installed and activating or deactivating the
   settings of your plugin. (Constructing Critical CSS, Combining JS and CSS, Deferring
   Unimportant JS, and İmage Optimization tools) At last I deactivated your plugin
   totally and the site pages started rendering seamlessly. I guess your plugin 
   needs a revision and an update .
 * Best Regards
 * The page I need help with: _[[log in](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fwordpress.org%2Fsupport%2Ftopic%2Ffatal-output-buffer-error%2F%3Foutput_format%3Dmd&locale=en_US)
   to see the link]_

Viewing 1 replies (of 1 total)

 *  Plugin Support [Josh (a11n)](https://wordpress.org/support/users/vitkory/)
 * (@vitkory)
 * [5 days, 17 hours ago](https://wordpress.org/support/topic/fatal-output-buffer-error/#post-18987567)
 * Howdy [@musa70](https://wordpress.org/support/users/musa70/),
   Thanks for the 
   report. Output buffering conflicts can happen when multiple plugins process page
   content simultaneously. In this case, Jetpack Boost’s optimization features and
   Real3D Flipbook appear to be conflicting.
 * As a workaround, you can keep Boost’s Image CDN and Page Caching enabled while
   leaving Critical CSS, Defer JS, and Concatenate CSS/JS disabled. These features
   use different approaches and shouldn’t trigger the same conflict.
   If you are 
   still planning to use Jetpack Boost, can you give that a try and let us know 
   how it goes?

Viewing 1 replies (of 1 total)

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 * 1 reply
 * 2 participants
 * Last reply from: [Josh (a11n)](https://wordpress.org/support/users/vitkory/)
 * Last activity: [5 days, 17 hours ago](https://wordpress.org/support/topic/fatal-output-buffer-error/#post-18987567)
 * Status: not a support question