MIME type ('text/html') is not a supported stylesheet MIME type

Yes this means the CSS could not be found and an error page was returned when you requested that CSS file. Because the error page probably has a Mime type of text/html instead of text/css, your browser displays that error. This is not a Honeypot-specific error, it's related to how your web server is delivering CSS files.

First step is to check your web site for that CSS file - visit mysite.com/system/files/honeypot/honeypot.css?sjnqlb and see what you get. Notice that ?sjnqlb is a string added by Drupal core for caching purposes - the real file is mysite.com/system/files/honeypot/honeypot.css and if that is found when you visit that web site you may have to clear your cache.

I found a couple of similar issues in the issue queue - #3010673: CSS in private files no good for anon users → and 💬 Chrome refuse to load honeypot.css Closed: cannot reproduce . I suggest you read through those and follow any relevant links. It sounds like some of this may come from trying to serve CSS files to anonymous users from the private file system.

No further information provided.