Thanks for keeping help.
About the AirPlay issue, in order to test in a simple environment I found a unmanaged switch cisco SG100D-08 to connect all three device, the NAS, iMac and AppleTV, all using fixed IP.
The NAS only plug in one network cable on port-1 and closed all VM stuff, restart RoonServer, AppleTV and iMac, still cannot make RoonServer on NAS see my AppleTV.
Additional information, don’t know where it related to the same cause, I also have the (quote from Mike) “Truly one of the more frustrating bugs ever” issue which ALL my android phone cannot connect Roon Core if the Core installed on NAS, but iOS work fine and everything work fine if the Core installed on any other Mac or PC, within my same network environment.
Seems in some kind of network or system environment will cause the RoonServer on NAS (not on Mac/PC) cannot communicate with some device.