Apple School Manager sFTP upload issues

Hi all,

I've been trying to upload our student details into ASM using the SFTP method, but I keep coming up against the same issue. I upload the zipped folder using Filezilla, which shows as complete, and the ASM screen shows that it is importing the data for a few seconds and then goes back to the "waiting for first SFTP upload..." screen.

Doesn't seem to make any difference whatever I do and it's becoming a bit of an issue as I am hoping to implement Managed AppleID this academic year and I'm just scratching my head. I've had some issues before where the formatting of the data was incorrect, but I got an error and a log for it, so I'm assuming that there is not an error as such but any help would be hugely appreciated.

Thank you