I am using Concrete 8.5.9 for this site and PHP 7.4. The theme is “Fundamental”, On my home page, when I am logged in, the top edit bar never shows up. On other pages it almost always shows up, but I’ve reports from other editors that it doesn’t show up sometimes on other pages.
I’ve cleared my browser cache and used firefox and chrome (both up to date) and have cleared the site cache multiple times.
I don’t know what the root cause is to that, but I’ve had it happen to me every now and then all the way from Legacy C5 to the 8+. Usually, I am using Chrome. Typically just a refresh of the page brings it back and sometimes I clear cache and it works again.
What happens if you add index.php to the url? Change mysite.com/about to mysite.com/index.php/about ? Does the editor bar display?
It could be the authorization header gets striped with certain server configurations.