Hey there, Wise__. Welcome to the community and a happy new year!!!
It seems like you've described a bit more about the issue in the title section, but it got cut off. Would you please let me know if you need to recover data from that drive? Do you hear any unusual sounds/noises coming from it? Do you even feel it vibrate or hear it spin-up when you connect it? Did you had any previous issues with it?
The first order of business should be to check the drive with a different USB cable and a different computer if possible, to see if the same thing happens. You could also try connecting it directly to the computer's motherboard via a SATA connection, as it sounds like it's an internal drive using an external enclosure. If you have no luck with that, I'd recommend that you go to Disk Management and check if the drive is recognized there:
How to access Disk Management in Windows to manage hard drives and post a screenshot (you can use imgur.com to upload the image) of what you see about the HDD there if it's detected.
If you don't need to recover data I'd suggest that you download the HDD manufacturer's diagnostics tool and test the drive, to see if anything unusual pops-up.
Hope that helps. Please let me know how everything goes.
Boogieman_WD