Try a different port and different ethernet cable.
WTF... I went over and touched my DNR-202L and the drive fail alarm was set off.. beep beep beep.. I didn't even have a chance to unplug the network cable.
Started laptop up to log in... no recording (still beeping)
unplugged network from router... and re-attached...
I don't think I touched the usb cable for the drive...
recording started again.... I'm using WD ultra passport 4TB drive... it's been full for a while... only 2 cams at the moment streaming...
p.s. my issues with "mydlink" are now straight.. I'm back online in there...
So I'm tempted to believe this might be related to your issue.. but this is my first time with such an issue...