Why does playing over DLNA to my Devialet is working so bad?

[Manfred]

My AV network is the following:

For DLNA Play and For Devialet AIR 

JRMC DLNA SERVER (Windows 10, separate room 36 TB Disk Space)->Switch (Linksys)->                                                                 Ethernet->D220 Pro | DLNA
         JRMC SERVER (Windows 10, separate room 36 TB Disk Space)->Switch (Linksys)->Media Renderer (JRMC Client, Windows 10)->Ethernet->D220 Pro | AIR

• The switch is not directly connected to a router, it is connected to a WLAN Bridge (AVM 1750E).
  
• Network topology: Internet->Cable->Cable Router (Old Fritz!Box with WLAN off)->Lan Bridge (AVM 1750E, Home Office)->WLAN Bridge (AVM 1750E, Living Room).
  

• Devialet AIR during playback works always fine. 
  
• Sometimes, after playback of a video, not audio, AIR stops working, restarting AIR helps in most cases, sometimes I must unplug power for my D220Pro . Then it works again.
  

For me up to now AIR has the best SQ, even better than playing through my Sotm txUSB card + iFI Power.

DLNA Play has the problem of stuttering in the beginning and for 24 bit 192 kHz stuttering all the time, even if Antivirus and Firewall is off.