won't play to Denon reciever

My setup is Synology NAS for music stored in FLAC format. MinimServer running on NAS. Audirvana on MacBookPro.
Problem is cannot get music to play on Denon AVR-X4100W receiver. Audirvana sees NAS, catalogs music, and will play music on my MacBookPro.
Audirvana sees Denon receiver, but won’t play, won’t start to play.
To test that the system works, I am using on of the Linn software products right now and it plays fine on this system, so it seems there is nothing wrong in the hardware in terms of being able to play.
How to get Audirvana to play music to my Denon receiver?
Thanks, in advance, for your advice.