Email Stuck Due To Domain Controller Not Reachable

This alert condition indicates a significant increase in the Categorizer Queue Length counter. This could indicate server performance issues, issues with Directory Service Access (DSAccess), the Active Directory directory service, or outages with key servers in the Exchange Server organization. An increase in the Categorizer Queue Length counter could lead to a lack of responsiveness in consulting Active Directory or in handing messages off for local delivery or SMTP.

Last modified April 17, 2020