SharePoint Online Session Expired

While working on a document edited in a browser users will receive a Session Expired or Timeout message after around 15 minutes. All users were using Internet Explorer 11.x

In my situation, this was caused because I had set an IP address restriction on my own SharePoint site (property IPAddressEnforcement).  Setting the IP address restriction through the UI also sets a timeout value for IPAddressWACTokenLifetime to 15 minutes. 

Below are the steps to increase the Session Time out by updating the IPAddressWACTokenLifetime value.

You should have SharePoint Online Management Shell to run these PowerShell commands.
Please Download using the below link. (SharePoint Online Management Shell works perfectly with Windows 10. You will see many error messages with Windows 7) 

https://www.microsoft.com/en-us/download/details.aspx?id=35588

1. Connect to SharePoint admin center and enter admin credentials.

    Connect-SPOService https://TENANTNAME-admin.sharepoint.com/

2. Run Command Get-SPOTenant | fl

    It will provide many Properties of the SharePoint admin center (as shown below).

3. Check if the IPAddressEnforcement: True and IPAddressWACTokenLifeTime: 15
     (15 minutes is the default time setup when IP Address Enforcement is True)
4. To increase the Session Time (i.e., IPAddressWACTokenLifeTime , we need to run the below PowerShell Command )

Set-SPOTenant –IPAddressWACTokenLifeTime 30

5. Run Command Get-SPOTenant | fl  to verify the property again.

Now the Session Expired or Timeout was increased to 30 minutes.