WD My Passport ssd 1tb will not mount on MAC

Macbook Pro 2016 and 2015 Sierra and El capitan.

We have had the HD mount in the past but its super spotty and now nothing. Disk utility does not recognize it.

I Just installed WD discovery and it sees the drive but still wont mount.

Hi kpphoto,
Does WD Drive Utilities also see the drive and if so does it pass SMART, the Quick, and the Extended tests? Also, have you tried using a different cable? You can open WD Drive Utilities from Apps in WD Discovery.