Title: Issue with Optimize Critical CSS Loading
Last modified: March 6, 2025

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# Issue with Optimize Critical CSS Loading

 *  Resolved [Manthan Kanani](https://wordpress.org/support/users/manthankanani/)
 * (@manthankanani)
 * [1 year, 3 months ago](https://wordpress.org/support/topic/issue-with-optimize-critical-css-loading/)
 * Getting an error while generating the CSS for the page while updating to 3.10.1
 * > Failed to generate Critical CSS
   > Hmm, looks like something went wrong. We’re still seeing an unexpected error.
   > Please reach out to our support to get help.
   > **Error: Failed to execute ‘btoa’ on ‘Window’: The string to be encoded contains
   > characters outside of the Latin1 range.**
    -  This topic was modified 1 year, 3 months ago by [Manthan Kanani](https://wordpress.org/support/users/manthankanani/).
 * The page I need help with: _[[log in](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fwordpress.org%2Fsupport%2Ftopic%2Fissue-with-optimize-critical-css-loading%2F%3Foutput_format%3Dmd&locale=en_US)
   to see the link]_

Viewing 9 replies - 1 through 9 (of 9 total)

 *  Plugin Author [Pete (a11n)](https://wordpress.org/support/users/dilirity/)
 * (@dilirity)
 * [1 year, 3 months ago](https://wordpress.org/support/topic/issue-with-optimize-critical-css-loading/#post-18346397)
 * Hey folks!
 * Apologies for the inconvenience.
 * We’re working on a fix for this. It’s hopefully coming in the next hour or two.
 *  Thread Starter [Manthan Kanani](https://wordpress.org/support/users/manthankanani/)
 * (@manthankanani)
 * [1 year, 3 months ago](https://wordpress.org/support/topic/issue-with-optimize-critical-css-loading/#post-18346551)
 * I reverted my latest version to older version but still I’m getting the same.
 * Thanks
 *  Plugin Author [Pete (a11n)](https://wordpress.org/support/users/dilirity/)
 * (@dilirity)
 * [1 year, 3 months ago](https://wordpress.org/support/topic/issue-with-optimize-critical-css-loading/#post-18346600)
 * Jetpack Boost 3.10.2 is now available. It should fix the problem.
 * Please update to that version and try generating Critical CSS.
 *  Thread Starter [Manthan Kanani](https://wordpress.org/support/users/manthankanani/)
 * (@manthankanani)
 * [1 year, 3 months ago](https://wordpress.org/support/topic/issue-with-optimize-critical-css-loading/#post-18346617)
 * > Failed to generate Critical CSS
   > Hmm, looks like something went wrong. We’re still seeing an unexpected error.
   > Please reach out to our support to get help.
   > Error: Maximum call stack size exceeded
 * This is now.
 *  Plugin Author [Pete (a11n)](https://wordpress.org/support/users/dilirity/)
 * (@dilirity)
 * [1 year, 3 months ago](https://wordpress.org/support/topic/issue-with-optimize-critical-css-loading/#post-18346632)
 * Ah, okay thank you, [@manthankanani](https://wordpress.org/support/users/manthankanani/)!
 * Another fix is incoming in a bit.
 *  Plugin Author [Liam Sarsfield (a11n)](https://wordpress.org/support/users/lsarsfield/)
 * (@lsarsfield)
 * [1 year, 3 months ago](https://wordpress.org/support/topic/issue-with-optimize-critical-css-loading/#post-18346853)
 * Hey [@manthankanani](https://wordpress.org/support/users/manthankanani/) we have
   released Boost version 3.10.3, which should resolve the `Error: Maximum call 
   stack size exceeded` Manual Critical CSS Loading issue. Please ensure that your
   browser cache is refreshed after updating the plugin, and before you generate
   the manual Critical CSS.
 * Please let us know if you encounter further issues, thank you!
 *  Thread Starter [Manthan Kanani](https://wordpress.org/support/users/manthankanani/)
 * (@manthankanani)
 * [1 year, 3 months ago](https://wordpress.org/support/topic/issue-with-optimize-critical-css-loading/#post-18346966)
 * The above Issue is resolved. Critical CSS generation has been resolved.
 * Thanks for taking the request with care.
 * Performace went down by 15% in mobile after the above issue arise .
 *  Plugin Support [fujifika (a11n)](https://wordpress.org/support/users/fujifika/)
 * (@fujifika)
 * [1 year, 2 months ago](https://wordpress.org/support/topic/issue-with-optimize-critical-css-loading/#post-18351670)
 * Hi there [@manthankanani](https://wordpress.org/support/users/manthankanani/),
 * Great to hear your issue is resolved! I’ll go ahead and mark this thread as solved.
   If anything else comes up, feel free to open a new forum thread—we’re always 
   happy to help.
 * Wishing you a wonderful day! 🙂
 *  Thread Starter [Manthan Kanani](https://wordpress.org/support/users/manthankanani/)
 * (@manthankanani)
 * [1 year, 2 months ago](https://wordpress.org/support/topic/issue-with-optimize-critical-css-loading/#post-18351675)
 * performance went up . It was my issue i disabled the cache for assets.
 * Thanks

Viewing 9 replies - 1 through 9 (of 9 total)

The topic ‘Issue with Optimize Critical CSS Loading’ is closed to new replies.

 * ![](https://ps.w.org/jetpack-boost/assets/icon.svg?rev=2818794)
 * [Jetpack Boost - Website Speed, Performance and Critical CSS](https://wordpress.org/plugins/jetpack-boost/)
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 * 9 replies
 * 7 participants
 * Last reply from: [Manthan Kanani](https://wordpress.org/support/users/manthankanani/)
 * Last activity: [1 year, 2 months ago](https://wordpress.org/support/topic/issue-with-optimize-critical-css-loading/#post-18351675)
 * Status: resolved