Settings - Main - Save Settings

There is something wrong with the server.
On settings page, open developer tools, then the console and send a screenshot of the contents of that console if there are errors.

If possible, enable OPcache. It's probably off.
Check SSL.

In one of the five "clean" installations of PHPFusion v.9 on the main settings page I have such a situation (attachment - screenshot). On other installations it's OK so I suspect an error in the file, but I don't know which one. This does not affect the operation of the site, but is intriguing

@Apis Which admin theme?

Only Artemis. But on other installations and the same theme is OK.

Fixed. Download latest Artemis from MP.

Thanks RobiNN. I enabled OPCache. I didn't know SSL was a requirement for PHP-Fusion. It's funny that the Site Protocol field in the settings menu gives you a choice though! I would have preferred without, but will now have to explore getting it.

The console gave me this:

This page uses the non standard property “zoom”. Consider using calc() in the relevant property values, or using “transform” along with “transform-origin: 0 0”. settings_main.php

Some cookies are misusing the recommended “SameSite“ attribute 2
Cookie “elftest” will be soon rejected because it has the “SameSite” attribute set to “None” or an invalid value, without the “secure” attribute. To know more about the “SameSite“ attribute, read https://developer.mozilla.org/docs/Web/HTTP/Headers/Set-Cookie/SameSite elfinder.min.js:11:6456
Cookie “elftest” will be soon rejected because it has the “SameSite” attribute set to “None” or an invalid value, without the “secure” attribute. To know more about the “SameSite“ attribute, read https://developer.mozilla.org/docs/Web/HTTP/Headers/Set-Cookie/SameSite elfinder.min.js:11:6516

MouseEvent.mozPressure is deprecated. Use PointerEvent.pressure instead. tinymce.min.js:2:8856
MouseEvent.mozPressure is deprecated. Use PointerEvent.pressure instead. tinymce.min.js:2:8856

​Firefox browser 85.0. Will upgrade to 87.0 now, see if that does anything.

SSL is not required but it can cause weird problems on live site. And also it's for security. You must enable it on the server first and then in cms.

OPCache is recommended for better performance.

Yep, using SSL fixed it.

Edit: I also did get (seemingly) random errors in the error log while doing things, nothing critical though. They have all vanished now since having SSL.