Backup Notification: Task status is: error

Symptoms

Plesk sends an email about failed backup even though scheduled backups being created successfully:

Backup task finished on host servername.domain.tld.
Task was created by server servername with guid (E5FE42EC-AAEE-4994-A8F4-0EDD0AE3DC4A)
Creation date is: 2015-Apr-21 04:01:50
Task status is: error
Dump full name is

However, today is not 2015-Apr-21 , and Backup manager does not show any warnings.

Cause

Previously failed backup task exists in tasks folder.

Resolution

RedHat-based Linux

Move all tasks from /usr/local/psa/PMM/tasks to another directory:

# mkdir /usr/local/psa/PMM/tasks.orig
# mv /usr/local/psa/PMM/tasks/* /usr/local/psa/PMM/tasks.orig/

Debian-based Linux

# mkdir /opt/psa/PMM/tasks.orig
# mv /opt/psa/PMM/tasks/* /opt/psa/PMM/tasks.orig/

Windows

Move all tasks from %plesk_dir%\\PMM\ asks to another folder.