UTF-8 addresses not supported on Office365


Zammad set an office365 channel to error because of an Email containing umlauts.
I understand that this issue ist actually not Zammad related but maybe someone has an idea what I might be missing here.

The SMTP Error is coming, if I’m not mistaken, from office365

E, [2023-05-23T09:12:29.321780 #1-112060] ERROR -- : Can't use Channel::Driver::Smtp: #<Net::SMTPSyntaxError: 501 5.1.8 UTF-8 addresses not supported
E, [2023-05-23T09:12:29.321923 #1-112060] ERROR -- : 501 5.1.8 UTF-8 addresses not supported
app/models/channel/driver/smtp.rb:93:in `send'
app/models/channel.rb:257:in `deliver'
app/jobs/ticket_article_communicate_email_job.rb:56:in `perform'
lib/background_services/service/process_delayed_jobs.rb:25:in `block (2 levels) in launch'
lib/background_services/service/process_delayed_jobs.rb:23:in `block in launch'
lib/background_services/service/process_delayed_jobs.rb:20:in `loop'
lib/background_services/service/process_delayed_jobs.rb:20:in `launch'

but from what I’m seeing, office365 should accept UTF8

what am I missing here?

  • Used Zammad version: 5.3.1-6
  • Used Zammad installation type: docker-compose
  • Operating system: debian 11
  • Browser + version: not relevant

Expected behavior:

  • Email should be accepted by office365

Actual behavior:

  • Net::SMTPSyntaxError: 501 5.1.8 UTF-8 addresses not supported

UTF8 is of course supported for the body of mails, but that doesn’t mean e-mail addresses with UTF8 are supprted. Don’t use umlaut in e-mail addresses. Just don’t

Zammad should encode and decocde UTF8 aliases since I believe Zammad 5.3 cleanly. If not this might be an issue. Possibly depends on how you try to send that mail.