Support

Before you begin, do read the boring stuff: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Content-Type-Options. It explains what this HTTP header does.

Most browsers will try by default to guess the content type of downloaded documents regardless of what the MIME header sent by the server. Let's say a malicious user to upload an executable file, e.g. a .EXE file or a Chrome Extension, under an innocent file extension as .jpg (image file). When a victim tries downloading this file, IE and Chrome will try to guess the file type, identify it as an executable file and under certain circumstances executing it. This means that your site could be unwittingly used to serve malware. The HTTP header above tells the browser to not try to guess the file type.

When it comes to SCRIPT tags, the source file MUST have a MIME type that indicates its executable JavaScript code, the canonical one being text/javascript. If your server does not send the MIME type at all, or sends the wrong MIME type (e.g. text/plain which means a plain text document, such as a README.txt file), the browser won't try to execute it as JavaScript and issue the error message you mentioned.

If the script with the problem is a URL pointing to your site you need to talk with your host. If it's a third party server, you need to talk to that third party.