When callers are placed on hold, they hear silence instead of hold music.
The option to play hold music is a setting that has been enabled system wide. From within the Skype for Business client, each customer may choose to use the default hold music, or a custom sound file.
It has come to Technology Services' attention that callers may hear silence when placed on hold, even though hold music is selected. To solve this issue, it may be necessary to re-select the hold music from within the Skype for Business client:
After performing these steps, you may want to test the hold music by having someone call you, then placing the call on hold.