After browsing the forum I found out that my problem is related to Roon and McAfee Firewall on my PC.
Some time ago Roon was able to playback music using my built-in Realtek audio card, but recently the ‘Audio Zone’ disappeared.
By turning off the firewall things work again.
Please could you help me with that?
My devices are:
Endpoint: PC running Windows 10 and Roon Version 1.5 (build 323) stable (64bit)
Core: NAS running QNAP QTS Version 4.3.4.0597 (2018/05/28) and Roon Version 1.5 (build 323) stable (64bit)
I look forward to hearing from you.