MKV problem

Hi, I have a WD TV Live + with latest firmware with a Wd HDD My Book 2Tb plug in back usb port. When I try to watch mkv files the wdtv freeze ramdomly, not always a the same place or after de same time. I see taht when the wdtv freeze the light on hdd turn off. Then I try to watch the same mkv files from my pc trought network, it work great without problem. Do I have something to do with the hdd to be ok to use it with the wdtv?

If it’s an USB3 HDD try watching the same files with the disk attached to the front port .