Mailgun: "Accepted" messages, but a long time for delivery (or non-delivery)

Question

I use Mailgun for a site that I maintain, usually Mailgun works fine, but I am facing some strange problem. My script calls the HTTP API to send messages using Mailgun, they then appear in my log as "received", but then they are "delivered" for a very long time, often not delivered at all and simply remain as "accepted". Has anyone experienced a similar error or can anyone suggest a way to fix this? I can guess it in the arguments provided by the API, but I cannot understand the problem for life.

The problem exists for different recipient domains and different times of the day.

The JSON message log is shown below. Of course, I changed the addresses and domains.

{ "tags": [], "timestamp": 1411498829.247304, "envelope": { "targets": "[e-mail]", "transport": "", "sender": "[e-mail]" }, "recipient-domain": "address.com", "event": "accepted", "campaigns": [], "user-variables": {}, "flags": { "is-authenticated": true, "is-system-test": false, "is-test-mode": false }, "message": { "headers": { "to": "[e-mail]", "message-id": "[e-mail]", "from": "\"the-site-in-question.com\" <[e-mail]>", "subject": "Dom, your password was reset." }, "attachments": [], "recipients": [ "[e-mail]" ], "size": 556 }, "recipient": "[e-mail]", "method": "http" } 

Answer 1

When a message is displayed as “Accepted” in Mailgun logs, it indicates that Mailgun has accepted this message and queued it for delivery. The message should be delivered quickly enough, but it can be queued for a while if you sent a large number of messages at the same time or if the ESP recipient suppresses messages from the IP / domain in your account.

I would recommend opening a support ticket through your Mailgun account and providing a part of the message identifier so that the support team can investigate the exact cause of these delays after sending the Mailgun message.

Answer 2

If this happens regularly, it is very likely that Mailgun has one of their low-level IP addresses. I assume this is the default value for free accounts, as they don’t want to “pollute” their good addresses with new users who cannot be serious / legit.

You can check the "quality" of the IP address on the site, for example, "Sender rating" . Locate this line in the Mailgun log of the delivered message:

 "sending-ip": "XXX.XX.XXX.XXX" 

If the "Sender Evaluation" shows an estimate in the 70s, this is your problem. Send Mailgun a support ticket, as Chris suggested, and see if they can get you to a higher quality IP address. I did this, and my emails are now sent from an IP address with a score in the 90s. There has been no delay since.