My Book Exterior Drive no longer accessible on my PC

I have a new WD My Book (8T capacity) purchased in January 2018. Until recently it has worked fine. Now, Windows 10 recognizes it in Devices and says it is “working properly”, but I can not access it, and its drive designation (K:) no longer appears on my PC. I have checked connections by unplugging and replugging. It is getting power and I can feel vibrations of disc.

The Data Lifeguard Tool software indicates that Short and Long tests cannot complete. Error message is “Too many bad sectors.” Help? Suggestions?

“Too many bad sectors” indicates that drive may be going bad and suggest to take a backup of important data before sending drive for replacement.

If my computers can’t access the drive how could I make a backup of the data?