I accidentally unmounted the External Hard Drive and now I want to re-mount it back

So I had the external 4TB Seagate Expansion Drive, and at one point I end up selecting unmount in Disk Utility when I tried running first aid.

Now I wish to mount it again, I tried pressing the mount button in Disk Utility. No response.

I tried ejecting, unmounting, and re-mounting the backup drive in Terminal through:

1. diskutil eject /dev/disk3s2
2. diskutil unmountDisk /dev/disk3s2
3. diskutil mount /dev/disk3s2

The resulting response is:

1. Volume timed out while waiting to eject
2. Unmount of all volumes on disk3 was successful
3. Volume on disk3s2 timed out waiting to mount

Insofar the hardware is blinking so I guess it's functional. I just like to ask if there are any solutions possible, or should I just click the mount button and wait for it, thank you.

Bonus: Here is the Disk Utility for the external drive insofar

There is a 3rd party app named Mountain that lets you control volumes on you mac. The app has a free trial period and costs around $6. Also available on App Store.