Fix: IIS not loading Unity WebGL project (stuck loading)

  1. Add the following to the web.config file.
<system.webServer>
 <staticContent>
 <mimeMap fileExtension=".mem" mimeType="application/octet-stream" />
 <mimeMap fileExtension=".data" mimeType="application/octet-stream" />
 <mimeMap fileExtension=".memgz" mimeType="application/octet-stream" />
 <mimeMap fileExtension=".datagz" mimeType="application/octet-stream" />
 <mimeMap fileExtension=".unity3dgz" mimeType="application/octet-stream" />
 <mimeMap fileExtension=".jsgz" mimeType="application/x-javascript; charset=UTF-8" />
 </staticContent>
 <urlCompression doStaticCompression="true" doDynamicCompression="false" />
 </system.webServer>