I just tried a Run now backup in preparation to updating to WordPress 4.4, and received the zip warning: Permission denied error. After deleting old backups through the end of November, I realized that although no error messages are being returned from scheduled backups, they are all of identical size, which suggests that they too have failed.
Backup my database and files (5 GB) weekly on Wednesday at 9:38 am, store the last 10 backups in /wp-content/backupwordpress-1e2a63f975-backups
6 backups completed Size Type Actions
December 27, 2015 – 11:09 am 451 MB Database and Files
December 27, 2015 – 11:06 am 451 MB Database and Files
December 23, 2015 – 10:10 am 451 MB Database and Files
December 16, 2015 – 9:39 am 451 MB Database and Files
December 9, 2015 – 9:43 am 451 MB Database and Files
December 2, 2015 – 9:41 am 451 MB Database and Files
I only recently took over management of this hosted WordPress site, and as far as I am aware, I do not have command line access to the server site.
I just clicked on the Support button to enable support, and started another backup, which failed, as expected, but will perhaps provide some new logging data.
Suggestions?