If you are running ActivEngage2 Server on a Windows 2003R2 system, you need to download the following hotfix from Microsoft. It is essential to apply this hotfix; otherwise you will not be able to activate an ActivEngage2 licence on a Windows 2003R2 system. After applying the hotfix, a power cycle is required for the changes to be applied.

For more information, please refer to the article Applications that use the Cryptography API cannot validate an X.509 certificate in Windows Server 2003 on Microsoft’s knowledgebase.