macos – External hard drive doesn’t show on Mac Finder

I am using macOS(Catalina)10.15.7 .My external hard drive is not showing in finder. It shows on Disk Utility but greyed and can not mount from there. I don’t want to loose anything from my hard drive. I have tried force mounting from terminal. So, i have followed these commands :

diskutil list

mount /dev/disk2

ls -la /Volumes/

sudo mkdir /Volumes/usb

sudo mount -t hfs /dev/disk2 /Volumes/usb/

But it shows :

mount_hfs: error on mount(): error = -1.

mount_hfs: Resource busy

mount: /Volumes/usb failed with 1

So, what can i do now to make it visible on finder without loosing any data