Thanks for posting here! I am sorry to know that you are having trouble connecting the Western Digital’s My Passport 500 GB through our Plugable 10 Port Hub. Let’s figure out what is causing the issue.
Some quick questions to understand the setup and the issue better-:
What are the make and models of the other devices connected through the Plugable 10 Port Hub?
Other than the portable hard drive, are the rest of the devices recognized by Mac?
Is the power adapter plugged into the hub and powering it up?
If all the devices and the power adapter are disconnected from the hub and the hub is connected to the Mac, does the blue LED bar on the hub light up?
If the hub is unplugged from the Mac and only the power adapter is plugged in, does the blue LED bar light up?
The blue LED bar lights up when the hub is getting powered either from the inbuilt USB port on upstream system or from the power adapter.
Once you post back with this information, we will figure out the next steps.
Thanks for your patience while we figure this out!