Error login to CDM

CDM version 10.2.4
Microsoft Windows 2008 R2 server

Can not log on to CDM, the user get this error after selection of server

Error message in log file:
2016-10-19 14:19:03,628 [4] ERROR Ibm.CognosDM.Api.PluginsManager – CDCGN00500E (null) Plugin DashboardPlugIn was loaded. ErrorFormat 0
2016-10-19 14:19:03,675 [4] ERROR Ibm.CognosDM.Api.PluginsManager – CDCGN00500E (null) Plugin Filing was loaded. ErrorFormat 0
2016-10-19 14:19:03,675 [4] ERROR Ibm.CognosDM.Api.PluginsManager – CDCGN00500E (null) Plugin TasksPlugIn was loaded. ErrorFormat 0
2016-10-19 14:19:20,993 [1] ERROR Ibm.CognosDM.App – CDCGN00025E ExceptionToken: Unknown [LayoutPersistErrorException] Error 0 System.NullReferenceException: Object reference not set to an instance of an object.
at Ibm.CognosDM.Storage.Bases.UserDataSetBase..ctor(String storageLocation, String user)
at Ibm.CognosDM.Storage.DataSetInstances.get_UserSettings()
at Ibm.CognosDM.App.ApplicationExit(Object sender, ExitEventArgs e)

Check this as first step:
Can you also reset the IIS to see if it helps? Type “iisreset” in a Command Prompt window.

If the issue still persist, can you check whether the SSL certificate for CDM is still valid in IIS?

1. From the Start Menu, launch “Administrative Tools – Internet Information Services (IIS) Manager”
2. Highlight ‘Default Web Site’ or the Server name in IIS.
3. Click ‘Bindings’ or click on ‘Server Certificates’ – there you see Expiration Date direct.
4. Highlight your entry for ‘https’ and choose ‘Edit’
5. Click ‘View’
6. Check the Valid from/to dates

In this case the Certificate on the IIS for the default web site had expiry.

Insert a new valid Certificate on the IIS server.

1. In the Internet Information Services (IIS) Manager console, under
Connections, select your server name.
2. Double-click Server Certificates.
3. Click Import.
4. Browse to and select the SSL certificate.
5. Enter the password for the certificate, and click OK.
6. Under Connections, select the website where the CognosDM-Server virtual directory is located. For example, select default.
7. Click Bindings. Select the https type, and click Edit.
9. In the SSL certificate window, select the certificate you imported, and click OK.
10. Close the Site Bindings window.
11. Select the CognosDM-Server website application.
12. Double-click SSL Settings.
13. Ensure that Require SSL is selected, and select Ignore in the Client certificates section.
14. Click Apply.

More information: