UNEXPECTED ERROR 500 5.0.0 - no-Email sending

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User olivier.g is experiencing an issue with email sending on their Discourse installation, receiving the error “UNEXPECTED ERROR 500 5.0.0 Unknown or unimplemented command.” They have tried troubleshooting steps, including checking telnet connections, discourse doctor, and email provider logs, but no emails are being sent. Their email settings are:

Seal suggests adding the line DISCOURSE_SMTP_AUTHENTICATION: login to the app.yml file to resolve the issue.

1

Hi
I installed discourse:

  • following the offical 30min tutorial
  • Ubuntu 20.04
  • I get to the “Congratulations, you installed Discourse” screen
  • I can register and it says that it sent an e-mail - but no e-mail reaches my inbox
  • also not, when I click “resend activiation”

What I tried according to the "troubleshooting email on a new discourse install):

  • Telnet: connection is ok (connected and service ready)
  • discourse doctor: “UNEXPECTED ERROR 500 5.0.0 Unknown or unimplemented command.” …This is not a common error. No recommended solution exists. Please report the exact error message above to h ttps://meta.discourse.org/
  • e-mail provider logs: there is nothing visible, that an e-mail would have been sent
  • Discourse Log:

Apache
root@ubuntu-2gb-fsn1-3:/var/discourse# tail shared/standalone/log/rails/production.log
lib/middleware/enforce_hostname.rb:23:in call'* *lib/middleware/request_tracker.rb:177:in call’
Rendered exceptions/not_found.html.erb within layouts/no_ember (Duration: 0.5ms | Allocations: 137)
Rendered layout layouts/no_ember.html.erb (Duration: 8.0ms | Allocations: 1280)
Rendered html template (Duration: 0.0ms | Allocations: 2)
Rendered layouts/email_template.html.erb (Duration: 0.3ms | Allocations: 30)
Delivered mail 8731fbdf-b6c8-49b5-86d5-08d8c32e5ac1@talk.absolutum. net (485.7ms)
Job exception: 500 5.0.0 Unknown or unimplemented command.
​

  • E-Mail Domain
    • My domain is: talk.absolutum. net
    • the e-mail sending domain is: norepoy@absolutum.net (so this is different from the domain
    • therefore I uncommented the "-exec: rails r “SiteSEttings.notification_email…” and entered my e-mail in the app.yml
  • I rebuild the app
  • I also changed the sitesettings.notification e-mail via the command line
  • I tried to use with or without TLS (in the yml) and port 587 and 25 (both ports are supported by my e-mail provider (also with rebuild)
  • I have no IP Adress in the mail domain
  • Results of the discource doctor:
    ==================== MAIL TEST ====================
    For a robust test, get an address from h ttp://www.mail-tester.com/
    Or just send a test message to yourself.
    Email address for mail test? (‘n’ to skip) [info@absolutum.net]:
    Sending mail to info@absolutum.ne t. . .
    Testing sending to info@absolutum.ne t using smtp .socketlabs.com:587, username:server34665 with plain auth.
    ======================================== ERROR ========================================
    UNEXPECTED ERROR
    500 5.0.0 Unknown or unimplemented command.
    ====================================== SOLUTION =======================================
    This is not a common error. No recommended solution exists!
    Please report the exact error message above to h ttps://meta.discourse.org/
    (And a solution, if you find one!)

Any idea, what I could try to solve the problem would be appreciated.
(sorry as new user I was only allowed to use 2 links, to I had to put some spaces in some urls)
Thanks
Olivier

2

Doh! I missed that. Since discourse-setup now asks for this that note is meaningless. Jeff, I’ll try to submit a PR removing that next week.

Did you put the proper address in discourse setup when it asked? Did you not understand the question? (which i can’t find the exact verbiage for now from my phone).

But that error is very strange, so I rather doubt that the notification email is the issue. What is the mail server? It shows no connection in its logs?

3

Thanks Jay for your reply.
Well, that’s what I entered (I removed user and password for mailer and the maxmind license key)
Does this look right?

Hostname : talk.absolutum.net
Email : info@absolutum.net
SMTP address : smtp.socketlabs.com
SMTP port : 587
SMTP username : myUsername
SMTP password : myPassword
Notification email: noreply@absolutum.net
Let’s Encrypt : info@absolutum.net
Maxmind license: license-text

4

For anyone that wants a final answer:

Edit your app.yml to add this line:

DISCOURSE_SMTP_AUTHENTICATION: login

There are mentions around the forum saying that one needs to edit a .rake file, but that is no longer necessary.