2TB Passport suddenly not detectable on XBox One

I bought the 2TB My Passport X on Nov 18, 2018, and it has worked great until today. Turned the XBox on, and the XBox is not locating the external HD. I went through the XBox troubleshooting, using the different USB ports, with no luck.
The light is on at the back of the external HD, so it appears to be working?

Any ideas on how to fix this?

Hi FWTX_Bob,

Try to connect My Passport X to another computer via USB and run complete drive test using Data Lifeguard Diagnostic to check for the issue with the drive.

Testing a drive for problems using Data Lifeguard Diagnostics for Windows

If passed, reformat the drive in compatible file format to use further with your Xbox.