Exchange 2019 Owa/ecp session timeout configuration

Now these values ​​are in  "HKLM:\SOFTWARE\Microsoft\ExchangeServer\v15\MSExchange OWA"

Hi,邓超

Welcome to the Microsoft forum.

Based on your description, maybe you need to set the ActivityBasedAuthenticationTimeoutEnabled or ActivityBasedAuthenticationTimeoutWithSingleSignOnEnabled parameter value to $true.When the two parameter’s value are both $false,it will not work even if you had set the ActivityBasedAuthenticationTimeoutInterval value.

Please try to run the following command:

Set-OrganizationConfig – ActivityBasedAuthenticationTimeoutEnabled $true.

More information about these parameters,you can refer to Set-OrganizationConfig (ExchangePowerShell) | Microsoft Learn.

If the value is already been set to $true ,but stll does not work,maybe you need to run:

Set-ItemProperty "HKLM:\SYSTEM\CurrentControlSet\Services\MSExchange OWA" -Name PrivateTimeout -Value 15 -Type DWORD

Set-ItemProperty "HKLM:\SYSTEM\CurrentControlSet\Services\MSExchange OWA" -Name PublicTimeout -Value 15 -Type DWORD

More details refer to: Exchange admin tip: Configure timeout settings for Outlook on the Web (techgenix.com)

And it is mentioned that “in January 2024, Microsoft started retiring activity-based authentication timeout for Outlook on the web” in this link : Activity-based authentication timeout for Outlook on the web in Office 365 - Microsoft Support.

I hope this helps.Please feel free to contact me for any updates.