IIS Express - HTTP Error 500.19 0x800700b7 on 'mimeMap' for 'fileExtension' set to '.svg'

And of course I find this answer after already posting my question:

Adding <mimeMap> entry Causes 500 for Other Static Content on IIS Express

So the issue is that my local IIS configuration has the modules already loaded, meanwhile the production environment doesn't. So to fix the issue for both environments you need to make sure the mimeMaps are unloaded before loading them.

The code is the following for the fix:

    <remove fileExtension=".json"/>
    <mimeMap fileExtension=".json" mimeType="application/json" />
    <remove fileExtension=".svg"/>
    <mimeMap fileExtension=".svg" mimeType="image/svg+xml" />
    <remove fileExtension=".woff"/>
    <mimeMap fileExtension=".woff" mimeType="application/x-font-woff"/>

Hope this helps others from wasting time looking for a fix.