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

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DETECTION OVERVIEW

Email Service Unavailable Error

Category

Service Degradation
Next in Service Degradation: FTP Access Denied Error

Description

An application or device had an excessive number of the SMTP 421 reply code, which indicates that email services are temporarily unavailable because of connection problems.

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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