In case of soft bounce it can be expected that email should go through. The current maximum retry time of 8 hours is too short if there is lots of email sent. Retry time doesn't scale well in case if most email sending is done during the office hours. Morning emails might be dropped before the less trafic nightly hours. Below is an ESP throttling response from Hotmail

ESP throttling: X → Y 'Z' Server response: 421 421 RP-001 (BAY004-MC2F19) Unfortunately, some messages from IP weren't sent. Please try again. We have limits for how many messages can be sent per hour and per day. You can also refer to http://mail.live.com/mail/troubleshooting.aspx#errors.

Mailgun bounce processing works great when a single sender is sending email to a broad audience. It does not work well when there are many original senders each with their own list of contacts.

Scenario:
- Company with 10 to 1000 employees.
- Company switches from a traditional in-house mail solution to Mailgun for all outgoing email.
- John, a typical employee in the organization, sends email to a customer, but spells the address wrong.

Traditional in-house system behaviour:
- John would get a Non-Delivery Report letting him know of his mistake. John would fix his mistake, and re-send the message. The customer would receive the email.

Mailgun-based system behaviour:
- Mailgun notes that the message cannot be delivered and records it as a "bounce". This information is accessible to the email administrator, but not to John.
- John is not aware that his email did not reach the customer. John waits for a response. Customer complains that John never sent him any email. John believes he did.
- John eventually gets the email administrator to look into it, and finds it in the bounce pile for the entire company.

Please implement an option to send Non-Delivery Reports to the original Sender, so that John would be notified that his message was not delivered.

As a side note, it would be beneficial if the Non-Delivery Report looked something like the traditional Non-Delivery Reports, so that software that recognizes these messages such as Outlook or Mailman would be able to understand them.

Thanks!

There are some delivery issues which usually warrant manual inspection and care by the administrative users. I feel that continuing to send emails to addresses that have ended up in the Bounces list would at least be one of them.

It would be convenient if the user could select certain common delivery issues like this and get a notification about them emailed to a specified email address. This email address could then be a mailing list for administrative personel who could look in to the error and see it they should act upon it.

It is possible to implement this with the webhook, but it is not very convenient. It is also possible to log in to mailgun every day to check the logs, but it is not very convenient either.

The ability to get an email for each error as it happens would be the first step. If you want to go further, add the option to receive daily digests of the errors.