After a couple of users complained, I discovered that since Monday our Discourse instance emails (via Mailgun) no longer seem to be getting through to those on Microsoft email tenants. This includes enterprise and general (e.g. hotmail.com , outlook.com ). On testing our deliverability, we didn’t hav…

[image] nathank: 4.7.650 The mail server [.27] has been temporarily rate limited due to IP reputation The line above is essentially saying that there is a reason for the throttling (beyond just receiving a large number of emails), and that is IP reputation. You can find your sending IP from e…

I’m having the same problem. But I was held via emailit [这张图片展示了一个 Outlook 邮箱界面，列出了多封带有发件人、主题、状态和创建时间等信息的电子邮件。 (由 AI 生成标题)]

[image] nathank: Your message does not contain a List-Unsubscribe header I don’t think it makes sense to have an unsubscribe link for a test message. All other messages from Discourse do have unsubscribe links. Right?

[image] nathank: This is the improvement suggestion: Your message does not contain a List-Unsubscribe header If I understand correctly, the lack of List-Unsubscribe header is just a suggestion from mail-tester.com , not necessarily the reason for the rejection by Microsoft. My guess is that…

I didn’t even know that Mailgun stores logs too - I guess that makes sense! First time I’ve had to delve in there. This is the rejection reason for almost all of them: 4.7.500 Server busy. Please try again later from [.27]. (S77719) [SY2PEPF00004FF3.ausprd01.prod.outlook.com 2025-06-27T03:22:50.7…

This is their reply: The error that you are seeing is ESP throttling, and this occurs whenever the recipient’s email provider has received a large number of emails from a specific IP/sender in a short period of time. Due to this, they will not accept messages for a certain period of time (usually …

Microsoft bouncing all emails from our self-hosted Discourse site (via Mailgun)

Product Support

Ethsim2 (Ethan ) June 26, 2025, 6:54pm 4

I agree, though I think the only exception might be staged users, since unsubscribe links aren’t present for them.

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Microsoft bouncing all emails from our self-hosted Discourse site (via Mailgun)

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