Wd ex4100 crashes


i also asked this question into the german forum but did not get an answer. now i hope that somebody here is able to help me. i am using a wd ex4100 nas with 4 X 8 tb hdd storage. i took the drive, created 4 shares and activated nfs to mount my network receiver to use the nas as recording target. this all works well and i can access the shares with my windows notebook. But my system crashes on an irregualar bais. sometimes all is fine for two weeks, sometimes it crashes every two days. The system is not reachable via ping or another network service so i have to unplug the power to restart it. In the system log is nothing to see which may cause this failure. The system is connectet via powerlan to my network but the powerlan adapters are still visible. i do not think that it is a hardware failure because it is my second wd device and the first one which was changed via rma had the same problems. has anybody an explanation for me?

Thanks a lot for your help,