Authentication with Exchange Server: registry value authenticationserviceUserHKCU\software\policies\microsoft\office\16.0\outlook\security

Policy ID: L_AuthenticationwithExchangeServer
Scope: User Configuration
Supported on: At least Windows Server 2008 R2 or Windows 7
Source: Microsoft 365 Apps / Office Administrative Templates (version 5568.1000)
Category: Microsoft Outlook 2016 › Account Settings › Exchange

Registry

authenticationservice

REG_DWORDUser

HKCU\software\policies\microsoft\office\16.0\outlook\security Current key

Enabled value: Depends on the option value
Element: Select the authentication with Exchange server.

Options
Item	Stored value
Kerberos/NTLM Password Authentication	9
Kerberos Password Authentication	16
NTLM Password Authentication	10
Insert a smart card	2147545088

Apply with .reg · CMD · PowerShell

.reg

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\software\policies\microsoft\office\16.0\outlook\security]

; Options (use only one)
; Kerberos/NTLM Password Authentication
"authenticationservice"=dword:00000009
; Kerberos Password Authentication
"authenticationservice"=dword:00000010
; NTLM Password Authentication
"authenticationservice"=dword:0000000a
; Insert a smart card
"authenticationservice"=dword:8000f000

CMD

:: Options (use only one)

:: Kerberos/NTLM Password Authentication
reg add "HKCU\software\policies\microsoft\office\16.0\outlook\security" /v "authenticationservice" /t REG_DWORD /d 9 /f
:: Kerberos Password Authentication
reg add "HKCU\software\policies\microsoft\office\16.0\outlook\security" /v "authenticationservice" /t REG_DWORD /d 16 /f
:: NTLM Password Authentication
reg add "HKCU\software\policies\microsoft\office\16.0\outlook\security" /v "authenticationservice" /t REG_DWORD /d 10 /f
:: Insert a smart card
reg add "HKCU\software\policies\microsoft\office\16.0\outlook\security" /v "authenticationservice" /t REG_DWORD /d 2147545088 /f

PowerShell

# Common: create the key
New-Item -Path 'HKCU:\software\policies\microsoft\office\16.0\outlook\security' -Force | Out-Null

# Options (use only one)
# Kerberos/NTLM Password Authentication
New-ItemProperty -Path 'HKCU:\software\policies\microsoft\office\16.0\outlook\security' -Name 'authenticationservice' -PropertyType DWord -Value 9 -Force | Out-Null
# Kerberos Password Authentication
New-ItemProperty -Path 'HKCU:\software\policies\microsoft\office\16.0\outlook\security' -Name 'authenticationservice' -PropertyType DWord -Value 16 -Force | Out-Null
# NTLM Password Authentication
New-ItemProperty -Path 'HKCU:\software\policies\microsoft\office\16.0\outlook\security' -Name 'authenticationservice' -PropertyType DWord -Value 10 -Force | Out-Null
# Insert a smart card
New-ItemProperty -Path 'HKCU:\software\policies\microsoft\office\16.0\outlook\security' -Name 'authenticationservice' -PropertyType DWord -Value 2147545088 -Force | Out-Null