Safepoint has a habit of disappearing when you need it most, it is also very slow and places a heavy load on system resources. Even with USB3 attached HDD data backs up via safepoint at a rate of around 0.7TB per day, so an initial Safepoint can take several days.
If you’re feeling confident, have a look at my alternative, faster backup solution here:
/WD-My-Cloud/Happy-accident-INCLUDES-AN-ALTERNATIVE-TO-SAFEPOINT
Good luck with your new My Cloud, it’s rather good once you get to know your way around it.
Nick