You may have noticed this issue message on your Trellis site:

Trellis is having trouble with your REST API. Critical CSS has been disabled.

Trellis will continue attempting to reach your REST API and Critical CSS will be enabled if Trellis can connect to your REST API.

Read on to find out what this message means and what to do about it.

Let's give the TL;DR on this before we get into any details - If you see this message in your WordPress admin, email the Trellis team at

Now on to some specifics, in case you are curious!

What does this notice mean?

The short answer is your site's Critical CSS is having trouble, and may not be serving because it's being blocked from accessing the necessary API (the service that allows us to deliver Critical CSS on your site). This is often because of some conflict specific to your site's environment. Critical CSS is one of Trellis's main optimizations that makes it so fast, and it's very important for speed and Core Web Vitals.

All of this means that you definitely want to give your attention to this notice right away.

Email the Trellis Team for Help

Since it's important for your Critical CSS to be working, it's best to address this issue when it comes up. There can be a lot of variables at play for why this is happening, so our expert team will be happy to help.

Reach out to and we'll be in touch to get started!

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