550 5.3.2 service currently unavailable

[Anonymous]

Has anyone ever received this error message? One of our reps attempted to send some Sales Insight emails and all of them bounced back with the 5.3.2 error code. We're not on any blacklists, but the rep's other emails not sent with Marketo make it through just fine.

[Anonymous · Accepted solution]

Hi Drew,
Error messages can be very well defined within the SMTP, however, their usage may not be accurate. According to our article, https://community.marketo.com/MarketoDiscussionDetail?id=90650000000Pc3RAAS, 5 is a permanent error, and 3.2 is System Not Accepting Network Messages.