This site is on shared hosting at 1and1.com. There are no file size limits. There are, of course, some reasonable memory limits, but I don’t know what they are, and they are not onerous enough to keep other backup plugins from producing backups of the same WP site.
In this case: Your plugin is getting so far as to generate a 175MB file called “zingUu7O” and then ten seconds later a 159MB file of the form “site-default-2-complete-2017-09-07-18-56-35.zip.DIRe1h”. (Having failed gracelessly, it also leaves a “.backup-default-2-running” file in that “wp-content/backupwordpress-28542540a1-backups” folder.)
