Hello @csan85!
Probably, your cache plugin causes the problem, please try to exclude CSS files from plugin, like here: https://www.trustindex.io/frequently-asked-questions#widget-box-does-not-appear-unless-i-am-logged-in-to-my-wordpress-page
Or, the second common problem is about the file permissions, perhaps, your server cannot read/modify some files from your filesystem, please check your Troubleshooting tab for more details, also you can send the content from there to here and we can check it as well then. (file permission settings are in wp-config.php and/or in your filesystem)
Feel free to write us, if you need further assistance,
Adam
Trustindex