Beginning in July of 2015, I've been unable to send mail using the Mailgun SMTP server using Mac Mail. To add a Mailgun account, I go to Mail > Preferences and under Account Information > Outgoing Mail Server (SMTP)

I choose the Edit SMTP Server List option. I select the options shown in the images.

When I hit OK, the account description in the Outgoing Mail Server (SMTP) briefly changes so that the "(Offline)" suffix is removed, but then it is quickly added back and I can't send with that account.

As suggested by Mailgun at https://documentation.mailgun.com/quickstart-sending.html#send-via-smtp,

I tried sending with swaks and was successful, though I had to change the password provided by Mailgun's example.

1 Answer 1


Go to: Connection Doctor in the Windows menu item...

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Then enable the log, or select show details to see if anything in the log helps you to see what the issue is...

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  • Thanks; why didn't I do this?! I tried this after reading your post; I'm told the username or password is incorrect, but still haven't been able to fix it. I can't mark this as correct b/c it hasn't fixed the problem, but thank you for help.
    – Brian
    Sep 5, 2015 at 23:07
  • Normally you don't use the username password of your account but the API key... Have you checked that? Sep 6, 2015 at 14:45

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