Email Not Sent Out

[Anonymous]

Hi All,

An email was set to be sent out to one of our customers but the marketo flow did not trigger the email, when i checked the info tab of the user in the database I saw this strange thing, 550 5.1.1  Recipient address rejected: undeliverable address: host mx2.virtmx-0006[137.166.68.1] said: 550 5.1.1 <... User unknown (in reply to RCPT TO command)

Does anyone know what is this for?

[SanfordWhiteman]

Exactly as stated: that's a message from the recipient's mailserver.

[Anonymous]

Thanks, I initially thought its the invalid email but when I emailed the user form the personal email it went through straight away, is there something I need to do in marketo, like white list IP or something, we noticed it because we had to individually send an email too, there must be many more in the DB like this. Is there something we can do about it

[SanfordWhiteman]

There's nothing specifically to do in Marketo. The recipient's mailserver is likely set to block all connections from Marketo -- the 550 error is just a spurious error to deter spammers (it's up to the mailserver to choose an error message, and it doesn't have to reflect the real underlying cause).  You can search the Community for many posts on these topics.