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.