The successful backup column contains the last date and time of the successful backup.
Backups with statuses “Completed” or “Completed with errors” are considered as a successful backup.
Accordingly, “Canceled” or “Failed” backup is considered as a not successful backup.
The monitoring system tracks the last backup date starting from 8th of December 2017.
Consequently, the successful backup date value will be blank if:
The backup was not performed yet.
The successful backup event was manually deleted.
The last backup was completed prior to 8th of December 2017.