Symptoms
Microsoft Outlook repeatedly prompts users for their credentials even if they enter the correct credentials. On the client side (Outlook), a "401" HTTP status code error message is logged. Some users have successfully mitigated this issue by scaling up their domain controllers.
Resolution
To fix this issue, install the following update:
Cumulative Update 11 for Exchange Server 2019 or a later cumulative update for Exchange Server 2019
References
Learn about the terminology that Microsoft uses to describe software updates.
