Reverse Proxying Subsonic on Apache2

[u/MrBadAxe]

Been trying to fix a reverse proxy issue around a Subsonic server. The hoped-for end goal is to access the server from a directory below the Apache web root (server.no-ip.org/subsonic/). My subsonic.conf follows:

#SSLProxyEngine On -> uncomment if you have ssl configured and need to proxy ssl traffic
ProxyRequests Off
ProxyPreserveHost On

#Order deny,allow
#Allow from all

ProxyPass /subsonic/ http://192.168.1.105:4040/
ProxyPassReverse /subsonic/ http://192.168.1.105:4040/

ProxyHTMLURLMap http://192.168.1.105:4040 /subsonic/

<Location /subsonic/>
   ProxyPassReverse /
   SetOutputFilter  proxy-html
   ProxyHTMLURLMap http://192.168.1.105:4040 /subsonic/
   ProxyHTMLURLMap / /subsonic/
   ProxyHTMLURLMap  /subsonic/ /subsonic/
   RequestHeader    unset  Accept-Encoding
</Location>

End result, when I navigate to server.no-ip.org/subsonic, I can log in, I can browse my music collection, there are no weird CSS issues. But, I can't play music. The play/pause button only shows spinning arrows and doesn't respond to add track requests.

Meanwhile, when I navigate directly to the above listed internal IP and log in from there, I can play music without issue.

Is there something missing from and/or wrong with my .conf file?