Expected a JavaScript module script but the server responded with a MIME type of "text/plain".

[tengfong00]

The command I use it just normal openbooks server

This is what the browser devtools console error came out with a blank white screen.

[evan-buss]

I encountered this issue on Windows 11. Are you using Windows by chance? I see this issue in the Go repository. It seems this is caused by incorrect configuration in the Windows Registry. Some applications (such as Visual Studio) modify the registry. See Stack Overflow.

I was able to fix this on my machine by modifying the registry seen below.

Before:

After:

After updating the "Content Type" entry, the web page loads properly.