When setting up the backup to a remote location, I get this error:
Error: Validation for transport “c1” failed: Could not upload test
file: Couldn't open remote file '/validate.tmp-27690-1501312901.txt':
It is very strange that cpanel does not include a proper hint/explanation/example exactly where this is needed (in the backup setup underneath the heading but before the input field of the backup path), since leaving it with the default "/" yields a permission error (which is hard to figure out and the quoted post above was the only hint available, as cpanel help does not explain it). Insufficient care and testing is again the reason for this. And it is over a year...perhaps get some interns to test?
(side note: The whole design of that backup setup is not very clear
and it is not straight forward either re which keys, etc. I suggest
you test a lot more with people who are not whm/cpanel experts and
who've no time, b/c such constraints reveal better what's needed.)