Thanks for reaching out! If you go into the caching tab of your Ezoic dashboard and open the 'Debug cache' section, you can select one of the top missed URLs. Upon opening this, you will see 'Reason Details' under the cache debug results. Take the value of this and copy it.
Now, travel back to your setting values and click on 'Vary Headers to be removed from origin'. Take the text that you've copied and add it as a header in this area.
Once this has been done, your site will start to rebuild its caching.