W52P - how do you get the Music on hold to work with 3cx?

[CWR]

Perhaps this unit is doing some sort of local hold that is not affecting the PBX?
Does it work at all - internal calls vs. external calls?
I have personally never seen this however.

There are some extension settings in 3cx worth playing around with regarding PBX delivers Audio. I do not have access to a 3cx system at the moment. But open the W52 extension in 3cx and look for it.
Changing these does not require any restart or reprovisioning of the device.