Web Server not serving audio file to every browser

The following is the communication between a web server I made in C and Internet Explorer. Everything is served but the audio file. Any insight as to why only the audio never gets served?

GET /castle/media/witchwoode.m4a HTTP/1.1
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko
Accept: */*
Referer: http://127.0.0.1:6006/castle/index.html
GetContentFeatures.DLNA.ORG: 1
Pragma: getIfoFileURI.dlna.org
Accept-Language: en-US
Accept-Encoding: gzip, deflate
Host: 127.0.0.1:6006
Connection: Keep-Alive

HTTP/1.1 200 OK
Server: web
Content-Length: 3017451
Connection: close
Content-Type: audio/mp4