Non Delivery Report

In this report, you can see data for messages that could not be delivered to the recipients, or about which there were complaints - for the last 32 days, today included:

non-delivery report screenshot

You can choose an arbitrary period within these 32 days. If the period is one day, then a detailed hourly breakdown of events for those 24 hours will be shown, if the period is more than a day, then the breakdown will be daily.

In this case, the “day” is defined by the UTC time zone.

You can filter events by selecting sender email address and / or recipient domain. Do not forget to click the "Apply" button after changing dates or sender/recipient filters to update the graph.

You can choose one of two data display modes:

All events - in this mode, each delivery failure event is counted and leads to an increase in the number of events of a defined failure type on the day that the event occurred (or per hour, if the statistics are broken down by hour). For example, a message which has been rejected as spam after 10 retries will be counted as sent 9 times and rejected as spam one time.

Unique events - this mode counts only events that are unique for a single message within a day (or an hour for an hourly breakdown). If during the day there were several repeated attempts to deliver the email, then only one retry will be counted. 

Events are divided into the following groups:

  • Retries. These are the so-called "soft bounces", i.e. replies from the recipient's server about the temporary impossibility of delivering the email. UniOne will make repeated attempts to deliver these emails over two days.
  • Unavailable. This group includes email addresses to which, according to UniOne’s information, delivery is impossible or prohibited. These can be addresses, messages to which have been repeatedly rejected by the recipient's server for a long time. Either the owners of the addresses have previously complained about the emails or have asked to add them to a permanent block list. Some of these statuses can be reset using the Email Search tool.
  • Non-existent. The recipient server replied that the address does not exist or is inactive. This is a "hard bounce", i.e. permanent error, with such an error it is pointless to try to send the same email again.
  • Rejected as spam. There were one or more delivery attempts, but the recipient's server rejected the letter explaining that it considers it to be spam. Also a "hard bounce".
  • Other non delivery. The email was rejected for reasons other than “rejected as spam” or “address does not exist,” or the reason could not be reliably identified. This is also a "hard bounce".

Statistics for the current day may be a little late as it takes some time to process and index the data. Usually, this delay will not exceed an hour.

If you are using projects, then in the upper left corner of the screen you can switch to viewing statistics for a single project, for the main project (main account), or select “all projects” to view summary statistics for all projects at once.