Iphone 5s error 1671

Hi folks,

My Iphone 5s won't update or even restore. It seems to be doing it but then the wheels fall off with the appearance of error 1671.

I've read and tried all the fixes listed but I note that the fixes don't actually tell you what 1671 is.

My phone has NEVER been jailbroken. My desktop has never been flagged as dodgy.

I've disabled security software, tried it on a Macbook, tried other USB ports etc. but to no avail.

Any ideas please?

Thanks in advance.

Paul