Net::SMTPSyntaxError: Net::SMTPSyntaxError

Technical assistance
1

Infos:

Expected behavior:

  • Could receive email via IMAP with OAuth on O365
  • Could send out email via SMTP with OAuth on O365

Actual behavior:

  • Receiving mail is working fine, no issue at all, so I expected the OAuth token has no issue.
  • Error return for send out mail: Delivery failed: “Unable to send email to ‘moses@contoso.com’: Can’t use Channel::Driver::Smtp: #<Net::SMTPSyntaxError: Net::SMTPSyntaxError>”

Steps to reproduce the behavior:

  • Setup an shared mailbox address from Channels > M365 channel
  • Configure email address from default group “Users”
  • Create a testing ticket, to mail at different domain / same domain, click Update, error message return after a while.

Check on log, but seems no useful log for trouble shoot even at debug level.
Could you please advise?

Thanks,

Moses

2

Looks like you need to configure your outbound email address.

3

I did configured the outbound address from channel, also the email address at group “Users”.
However, since my mailbox login is using default xxx.onmicrosoft.com domain, and the mail address is xxx.com. I’m not sure if this affect, but if I set outbound address by using these 2 mail address, still not success.

4

If you have your domain setup in 365, it should work with that as your login as well. Your email address should be xxx.com and xxx.onmicrosoft.com. Setting them up as different may be your issue.

Perhaps you need to review your MSO setup.

5

The user most likely isn’t allowed to use SMTP for sending. It’s a configuration issue on Microsoft 365 side.

6

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