ExtraHop named a Leader in the 2025 Forrester Wave™: Network Analysis And Visibility Solutions

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DETECTION OVERVIEW

Email Mailbox Unavailable Error (550)

Category

Service Degradation
Next in Service Degradation: Email Service Unavailable Error

Description

A client received an excessive number of the SMTP 550 reply code from the SMTP server, which indicates that the client is frequently sending email to a mailbox that does not exist. Remove the mailbox address from the sender's mailing list.

Associated content

Announcing The Forrester Wave™: Network Analysis And Visibility Solutions, Q4 2025

Network analysis and visibility solutions remain underrepresented in enterprises. Find out why in this preview of a new Wave report.

Report
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ExtraHop® Named a Leader in First-Ever Gartner® Magic Quadrant™ for Network Detection and Response — ExtraHop

ExtraHop® Named a Leader in First-Ever Gartner® Magic Quadrant™ for Network Detection and Response

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Periodic Table of Use Cases

What else can RevealX do for you?

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