Core Issue
After a customized Music on Hold (MoH) file is installed on Cisco CallManager Express, when the caller is put on hold, the held caller hears loud and garbled music.
Resolution
In order to resolve this issue, make sure the file format is correct. If the file format is 128 KB 16-bit then the MoH music is garbled. Change the format to 64 KB 8-bit.
Refer to moh (telephony-service) for more information.