Failed to generate Critical CSS

I experienced this critical error too
it happened when I upgrade to Version 3.0.2

and update WP t0 6.4.3

And I have the same problem when updating the plugin to 3.0.2 and WP to 6.3.4.

Oh, it’s not just me then. The actual error message is “Expected an associative array, received ‘NULL'”

• This reply was modified 9 months, 4 weeks ago by HarryAdney. Reason: added more info

I don’t even have an error message fixed. In the process of generating critical CSS, the progress bar constantly goes far ahead, then rolls back. An error message may pop up for one second (“Failed to generate CSS”), disappears after a second, and the generation process begins anew. Yesterday, the page with Jetpack Boost was not closed all day, only in the evening it was possible to generate critical CSS, and the result lasted for some time, and did not self-update, as it began to happen after this error appeared, but since the page was published on the site, today I generate critical CSS again all day.

It is a pity that the optimization function for loading important elements in CSS is broken, I will really hope that the error will be fixed, because it significantly speeds up my site!

Hi everyone,

I’m really sorry to hear you’re encountering issues with generating Critical CSS after updating to WordPress 6.4.3 and Jetpack Boost 3.0.2. We’ve been trying to replicate the problem on our end but haven’t been successful yet, suggesting it might be related to specific settings or environments.

To help us dig deeper and get to the bottom of this, would any of you be comfortable sharing your site URLs? This will greatly aid in our investigation. If you’re concerned about privacy, please feel free to share the details privately through our contact form. Initially, the page features a form where you can submit your question, and our AI attempts to provide an answer. If it doesn’t find a suitable response for your query, you’ll then have the option to use the contact form to get in touch with us directly.

We appreciate your patience and cooperation as we work through this together. Looking forward to getting your sites up and running smoothly again!

Thank you!

Hey there,

I wanted to drop by with some good news! Our team has been hard at work, and they’ve successfully identified and fixed the issue that was causing the Critical CSS generator to time out. This fix was implemented a few days ago.

We’re eager to ensure that your experience with Jetpack Boost is as smooth as possible. So, if you could spare a moment, please let us know if the problem still persists on your end.

Your feedback is greatly appreciated, and it helps us fine-tune your experience with our plugin. Thanks for your patience and ongoing support!

Best regards,

Nope, issue is still here

Hey Alin, just tried it and so far, so good Many thanks to you and your techies!

Hi @harryadney,

Hey Alin, just tried it and so far, so good Many thanks to you and your techies!

I am happy to hear that.

Hi @wattaman,

Nope, issue is still here

I am sorry to hear that. Can you please share your site URL so we can investigate this further? If you want to stay private, you can share it through our contact form here.

Hi @scorpionka and @zupaazhai, to ensure we can give you the personalized support you deserve, could you each create a new support thread here? This helps us keep track of your issues more efficiently. Thanks so much for your understanding and cooperation!

Hi @alinclamba

after I updated to 3.0.2 by today, I still got same error,
I try to inspect at Network tab of browser, it request to

/wp-json/jetpack-boost-ds/critical-css-state/action/set-provider-css

I got
“404 Not Found”
nginx/1.18.0 (Ubuntu)

from my server

• This reply was modified 9 months, 3 weeks ago by zupaazhai.

Hi @zupaazhai,

To provide more effective assistance, could you please start your own new thread? You can either share the URL of the site publicly for further investigation, or use the contact form to share it privately.

Thank you!

Hi @wattaman,

Do you have updates about that? We usually close inactive threads after one week of no movement, but we want to make sure we’re all set before marking it as solved. Thanks!