Net::SMTPAuthenticationError due to wrong mailgun server

Product Support Self-hosting

AI-generated summary

hostingpeep reported a Net::SMTPAuthenticationError while setting up email for their Discourse installation using Mailgun, preventing sign-up emails from being sent. They confirmed Gmail could send emails to the admin address, suggesting the issue was configuration-related, and suspected plain authentication might be the culprit. They shared their Discourse doctor output and app.yml configuration, and referenced several similar threads for context. In post 2, hostingpeep resolved the issue by realizing they were using the US Mailgun server instead of the EU one — a simple region mismatch. pfaffman acknowledged the commonality of this mistake, confirming others have faced the same issue.

1

Hello Community! after installing discourse I am struggling with email setup. I did necessary setup with mailgun. Sending email to admin@domain.com from my mail.google.com (normal gmail) is working fine. But when I use it with app.yml config, I get following error and did not receive an email. It is very 1st email, I am not able to sign up for my forum.

I think it is due to plain auth. I read it on one of thread. But I don’t know about solution.

Discourse doctor:

1115×670 71.1 KB

app.yml
914×353 67.4 KB

I have taken look over some other smtp threads in this problem.

Thanks for your time and support.

2

Okay, Found the solution. I was using US mailgun server but actually it is EU. So it was mistake.

3

I’ve gotten stuck by that one too!