MBL offline after a few hours of operation

I'm not really a beginner regarding my MBL (WDBACG0010HCH-00) but since a few months the drive looses it's network connection and cannot be accessed, neither via SSH nor via HTTP, also no ping response. No matter how I configure it (DHCP or static), it works fine for a few hours and then stops without a reason. I did a few resets, restored the factory settings but nothing helps. After taking it from power and replugging it the drive will work for something like half an hour to two hours. I'm out of warranty already so I have nothing to loose and I would not want to replace it although at the moment there's no data on it. Is there any way to find out what makes the drive stop connecting? I'm willing to try anything :-) but I don't know where to start, I'm just a user.
I'm on a Mac by the way.
I'd be willing to donate a certain amount of Euros to a charitable institution to express my gratitude if one helps me to find a way to make the drive work well again. I simply can't use VPN or Transmission if the drive falls asleep like sleeping beauty :-)
Thank you very much!
René