Roon RAAT and "An audio file is loading slowly"

[K4680]

Hello, since I also wanted to test Roon, I installed Roon on a Mac Mini.  Two days of testing and playing, looks good.  Suddenly, Qobuz's files are no longer loaded, before the song title a little blue stroke, that's all.  After 50 minutes, the title started to play.  Frustration!! At first suspected Qobuz, because the Qobuz player was also installed on the Mac I tried to play songs, no problem is going great.  Back to Roon, the same problems! Roon uninstalled, all database entries deleted and Roon reinstalled!  All the best, but only one day!  Slow download of Qobuz, titles from Melco played flawlessly!  Roon deleted again and reinstalled, the same after a short time again.  Since I still had an Intel NUC7i7 from another project, I installed Roon-Rock on it, and since a week the NUC runs without any problems!   The NUC is connected via Ethernet, the next test is the connection to the Devialet via USB.  
Features NUC: i7, RAM 16GB, SSD.M2/128GB

My internet connection: Vodafone Cable 500/50 Mbit/s, FritzBox 6590.