G-Drive SSD USB-C will not accept back ups

My G-Drive slim SSD USB-C, (500Gb) which is less than half full, is refusing to down load back-ups from my MacBook. It gets to about 600Mb from a few Gb, then the time estimated goes to around an hour, & it comes to a stop. The casing gets quite warm, which I have never noticed previously.
Is this a fault with the G-Drive, or the MacBook?

It could be due to either depending on how another process fairs. If you are willing I would recommend erasing the drive if it contains only backups with Disk Utility and then trying to do a Time Machine backup again.

If you are on Mojave, there have been known issues with certain applications that block Time Machine from continuing. The official Apple forums are filled with such cases. In some cases you need to track down specific apps and exclude them from the backups.

Many thanks for your prompt reply.
I should have mentioned that my MacBook is running Sierra. Erasing my back-ups seems a bit drastic since it seems quite likely that it will not be possible to do backups with the present set-up.
I suspect it is a MacBook fault since I have had other issues which appear unresolvable.