Any attempt to run a full backup ends in <empty response>
Other sites on the same shared host are able to successfully backup
Checked and removed old large files, excluded 2 mp4 video files from backup. DB cleanup. Re-installed latest version of WP (re-install version 4.9.8). Disabled all plugins - except WPMU dashboard and snapshot pro - no change.
1 item in Error log monitor plugin: Fatal error: Allowed memory size of 805306368 bytes exhausted (tried to allocate 67108872 bytes) in xxxxxxxx/public_html/wp-content/plugins/snapshot/lib/Snapshot/Helper/Utility.php on line 534