Hey there, Dave!
Unfortunately a drop like this could have damaged the internal particles of the drive itself.
Do you hear any unusual noise coming from the drive when you connect it?
Do you see the drive in Disk management on your computer? Can you share a screenshot of it?
You can also check if your drive has a hardware encryption or not, if it doesn't you can get it out of the enclosure and connect it directly to your computer through a SATA port. It might let you access it.
If it is in fact a physical damage, we won't be able to troubleshoot it. Which basically leaves you with contacting a professional data recovery company for assistance and retrieving of your files. Other than that, I'm not sure you will be able to fix the...