Timemachines failed to find My Cloud

Hi guys,

I am currently using a Macbook Pro Retina with OSX 10.10.2. I had recently bought a Western Digital My Cloud 2TB network storage, and it was stated by the manufacturer that it supported time machine backup. But I am facing problem that I cannot keep logging into this drive through network, it results that I might be able to connect and do the backup today, but tomorrow, my time machines backup unable to find the drive, I had being struggling for this quite some days. Wishing anyone within the forum could provide me some idea on how to overcome this problem.

Thank you.