Have you tried the DAC with other digital sources, such as a CD player? If so, and it seems to work, then your problem is either: 1) Internet; 2) The server; 3) the hand off from server to DAC.
Servers are networking computers that are gussied up to look like audio components. They are subject to the same foibles that computers are. Have you ever had a computer that was working fine and suddenly doesn’t “see” something, such as a printer? The first step is to power everything down and then restart them. If that doesn’t work after a few tries, then it may be that a software update in the server, or the DAC, may have “bricked” these two components