weird … some questions;
* can you clear AO’s cache?
* can you clear Cloudflare’s cache?
* do you have any errors in your php errorlog?
* are there any other files in wp-content/cache/autoptimize/css and are those files empty as well, or not?
* do you also have this problem when “inline&defer” is not used?
* can you try optimizing JS as well for a second to see if those files are emtpy as well?
frank
* I cleared the cache, still same
* can’t clear Cloudflare’s cache because i have no access to the server
* same goes for the errorlog
* the problem is same with and without inline
* now that you mention it i see that the js is also empty.
And the funny thing is, when i don’t select inline css, i can’t find any autoptimize file.
next up;
* regarding cloudflare; cloudflare has a dashboard you an log into where you can clear the cache, cfr. this support article
* regarding php errorlog; that one is on your own server, not cloudflare. maybe check with your hoster?
* are there any other files in wp-content/cache/autoptimize/css and are those files empty as well, or not?
the alternative approach could be to selectively disable/ enable plugins (and briefly switch themes) to confirm my suspicion that this is a conflict of some kind.