Snapshot freezes when creating full bckup

Hi, I have never been able to finish a full backup (incl. all files and database). All goes well until the backup reaches the media backup. Then, the screen goes blank after a minute or so. I am hosting (shared) with Godaddy, run php 5.6 with 32MB upload, 300ms timeout and 256MB WP memory.

This happens on all my WP multisites which are quite large. I regularly keep WP, themes and plugins updated. Smaller single installs have no problem on the same server.

Any insight? I have granted you support access.