Title: Critical css issue Last modified: June 24, 2021 --- # Critical css issue * Resolved [lettisofa](https://wordpress.org/support/users/lettisofa/) * (@lettisofa) * [4 years, 10 months ago](https://wordpress.org/support/topic/critical-css-issue/) * Hello I installed the plugin but I got some ccss errors -> [https://prnt.sc/16lwkzb](https://prnt.sc/16lwkzb) I’m running it with Jetpack and WP Super Cache too. Webserver Apache + Nginx How can I fix it? Thanks Viewing 8 replies - 1 through 8 (of 8 total) * [deathlynotes](https://wordpress.org/support/users/deathlynotes/) * (@deathlynotes) * [4 years, 10 months ago](https://wordpress.org/support/topic/critical-css-issue/#post-14593622) * Hello there, * I am glad to help! * Could you bypass Cloudflare activating the Developer mode and test the site again, please? * Here you can find the information to bypass the Cloudflare access: * * [https://support.cloudflare.com/hc/en-us/articles/200168246-Understanding-Cloudflare-Development-Mode](https://support.cloudflare.com/hc/en-us/articles/200168246-Understanding-Cloudflare-Development-Mode) * After activating the DevMode, please deactivate all the cache plugins and optimization plugins you have installed on your site, leaving only Jetpack Boost enabled, and test it again. * Let me know if you have any questions. * My best regards, * Michelle * Thread Starter [lettisofa](https://wordpress.org/support/users/lettisofa/) * (@lettisofa) * [4 years, 10 months ago](https://wordpress.org/support/topic/critical-css-issue/#post-14595882) * I don’t use Cloudflare. I deactivated all plugins but still got same ccss errors. Please take a look tinyurl.com/8rksnrvr * Thread Starter [lettisofa](https://wordpress.org/support/users/lettisofa/) * (@lettisofa) * [4 years, 10 months ago](https://wordpress.org/support/topic/critical-css-issue/#post-14595972) * Ok. If I disable Jetpack it works. Can I use Jetpack or not ? It is compatible? * Thread Starter [lettisofa](https://wordpress.org/support/users/lettisofa/) * (@lettisofa) * [4 years, 10 months ago](https://wordpress.org/support/topic/critical-css-issue/#post-14600075) * Resolved. On nginx it is not possible to use X-Frame-Options: DENY. * Thread Starter [lettisofa](https://wordpress.org/support/users/lettisofa/) * (@lettisofa) * [4 years, 10 months ago](https://wordpress.org/support/topic/critical-css-issue/#post-14600101) * Can I set add_header X-Frame-Options “SAMEORIGIN”; on nginx ? It will block the plugin ? * [Karen Attfield](https://wordpress.org/support/users/wpkaren/) * (@wpkaren) * [4 years, 10 months ago](https://wordpress.org/support/topic/critical-css-issue/#post-14626840) * Hi [@lettisofa](https://wordpress.org/support/users/lettisofa/) * Apologies for the delay in getting back to you here. * You can certainly use Jetpack alongside Jetpack Boost, the two are compatible. * With the Critical CSS errors you were initially seeing, to give some more context this means that the specified URL is loading content from a different domain or protocol. It usually means the specified URL is a redirect to an external site. It may be worth deactivating any plugins which add redirect URLs to the site for the duration of generating Critical CSS. * As for the X-Frame-Options issue, it is correct that when a site has X-Frame- Options: DENY in its HTTP headers, browsers will refuse to load it inside iframes. That currently breaks our local Critical CSS generator in a way that looks a lot like a cross-domain error. This is an issue our developers are working on but there is no timeline on when it will be implemented at this stage. * As for whether or not you can set X-Frame-Options to SAMEORIGIN – I have reached out to our developers for more information there. * Do let us know if you have any further questions in the meantime though! * Thread Starter [lettisofa](https://wordpress.org/support/users/lettisofa/) * (@lettisofa) * [4 years, 10 months ago](https://wordpress.org/support/topic/critical-css-issue/#post-14630027) * Thanks * Plugin Support [Dan (a11n)](https://wordpress.org/support/users/drawmyface/) * (@drawmyface) * [4 years, 10 months ago](https://wordpress.org/support/topic/critical-css-issue/#post-14630819) * Hi [@lettisofa](https://wordpress.org/support/users/lettisofa/) * Our developer confirmed that `X-Frame-Options SAMEORIGIN` works fine with Jetpack Boost. It only doesn’t work with `X-Frame-Options: DENY`. * We hope to make this easier to handle in a future update. * Hope that helps! Viewing 8 replies - 1 through 8 (of 8 total) The topic ‘Critical css issue’ 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/) * [Frequently Asked Questions](https://wordpress.org/plugins/jetpack-boost/#faq) * [Support Threads](https://wordpress.org/support/plugin/jetpack-boost/) * [Active Topics](https://wordpress.org/support/plugin/jetpack-boost/active/) * [Unresolved Topics](https://wordpress.org/support/plugin/jetpack-boost/unresolved/) * [Reviews](https://wordpress.org/support/plugin/jetpack-boost/reviews/) ## Tags * [ccss](https://wordpress.org/support/topic-tag/ccss/) * 8 replies * 4 participants * Last reply from: [Dan (a11n)](https://wordpress.org/support/users/drawmyface/) * Last activity: [4 years, 10 months ago](https://wordpress.org/support/topic/critical-css-issue/#post-14630819) * Status: resolved