I've got a black Now TV Box (based in Roku 2) running Plex Classic 3.1.6. The server is a Intel NUC running Free NAS & Plexmediaserver 1.0.0.2261 .
On the Plex Client MP3's play without a problem, but most AAC/MP4 do not. Seems to be mainly a problem with 256Kbitrate files. Some but not all 128KBitrate files work.
The source of the files are CDs using iTunes to rip them. They are not copy protected (DRM), and work fine when I connect to the Plex Media Server using a browser management console or with Windows media player.
Any help much appreciated