You can only upload tracks that are either .mp3 or .m4a audio format to your Live365 library. 

The files should be encoded at 128 kbps or lower bit rate and 44.1 kHz sample rate. Also, be sure the channel mode is "Joint Stereo" and the bit rate mode is "constant" (CBR), not "variable" (VBR). 

The system can handle lower bit rates, but higher ones are not supported at this time.