Snapshot stalling out – can't create backup

This is the second time in a row I’ve had this issue with snapshot.

I am trying to move my client’s site to my server. We have set the max execution time to 250 -but the snapshots continue to stall out at 70% (they stop after completing 80% of the media uploads).

I have granted wpmu support access if that is helpful.

EDIT by Predrag: Removed login details