"MIME type is not a supported stylesheet MIME type, and strict MIME checking is enabled"

Our software is in a live pilot stage now, but there are frequent inconsistencies that are blocking end users from using the software successfully. These types of issues are rarely reproducible by us at Smartcube, but several independent users keep encountering similar blocking issues that will sometimes go away after several minutes or several refreshes, and other times just stay consistently not working.

In this case, a supplier is trying to upload an equipment CSV file from a filled in template we provided, and it works fine for us, but the user is getting the attached errors.

Have you seen this kind of thing before? Do you have any suggestions to fix these types of problems? Other users are having similar failures when working with template-based CSV imports.


This one is a new issue I have never seen before. Do you have any insights on which use case this occurs? Is it just the CSV import, or other cases as well?

It would of course be great if it was reproducible in Dev by some of you. We would ideally like to take a look at the “Networks” pane of the developer console in the browser to inspect the response.

No, it’s not consistently reproducible. I have personally never been able to reproduce it. But several clients have very similar problems.

The most frequent case is CSV imports, but similar things also happen to several users when the application loads after logging in. This is another issue that we are unable to reproduce, but it affects many users sporadically.

1 Like

Thanks, we will see if we can get anything out of that screenshot, but I’m afraid that it is only a small probability that the issue will be solved without being able to reproduce it somehow (or to pinpoint which case it occurs consistently).

If you can reproduce it somehow - please take a look at the response (in the Networks tab), and let us know.


Just a small note from one of our tech guys. These errors / urls are not familiar. The hypothesis is that some browser plugin might be causing this.

It would be great to learn a bit more about

  • consequence, what feature is not working due to this
  • browser version etc of those affected, maybe a full screenshot might reveal that + potential plugins.
    …and with that, maybe a step closer to being able to reproduce.