Thanks for getting back to us, pwwwayne. We apologize that the information wasn’t helpful. We share the how-to’s first since we don’t know the level of a user’s experience.
If a USB device doesn’t work with Mac - Apple Support -- While the title of this page of the macOS User Guide doesn’t exactly match your issue, the steps provided can help.
How to use safe mode on your Mac - Apple Support -- If the external drive still ejects on it’s own, please restart your Mac in safe mode and test the issue a bit. Whether or not the issue happens while in safe mode, restart your Mac normally to exit. Also, please be aware that it takes longer to start in safe mode:
Safe mode prevents your Mac from loading certain software as it starts up, including login items, system extensions not required by macOS, and fonts not installed by macOS. It also does a basic check of your startup disk, similar to using First Aid in Disk Utility. And it deletes some system caches, including font caches and the kernel cache, which are automatically created again as needed.
If the issue didn’t happen while in safe mode, test the issue again after a normal restart. The issue may have been resolved.
Please let us know the results when you're able.
All the best.