Refused to execute script from 'https://ourmain.js' because its MIME type ('text/html') is not executable, and strict MIME type checking is enabled

This problem is inconsistent, it works for some users and not for others. Also, it works for some users on a browser and not another.


Can you check (whenever it doesn’t work) in the browsers developer tools (F12) in the network tab if .js file is actually delivering Javascript code and not some error message?

Hi Lukas, thanks for answering. I get a 200, but when I try to look at the preview it says

If you’re seeing this message, that means JavaScript has been disabled on your browser , please enable JS to make this app work.

Even though Javascript is enabled in my browser


Which request is it? The /index.php?module=Proxy&action=getCoreJs one should not respond with any website, but with Javascript

Hey Lukas,
I don’t see the request mentioned. The request I mentioned before was our bundle.js one.
After searching a little bit more, I’m wondering if this has something to do with react.
We startMatomo on our componentDidMount, and on componentDidUpdate we make a window.URLChanged() call.
Do you think it can be related? I found a post on stack-overflow that mentions it but without many details


Do you get the error on your tracked website or when opening the Matomo UI? (I assumed the latter)

I get it on my website

And is the .js file in the error message the matomo.js or another file? Because in the latter case it might be unrelated to Matomo.

The js file in the error is our bundle.js which calls matomo. I’m assuming it’s from Matomo as we don’t run any other scripts

But the error indicates that the webbrowser is requesting the bundle.js, expects from the webserver to get back a Javascript file, but actually recieves HTML (text/html) and therefore refuses to execute it.