Accessing Custom Interface aggregate on KAppBoss in Background Thread

My custom Interface IID_ABCIINTERFACE aggregate on KAppBoss .

when I do this

        IApplication* iApplication = GetExecutionContextSession()->QueryApplication();

        InterfacePtr<IQPPDPAssetCacheManager> iQPSAssetCacheManager(iApplication, UseDefaultIID());

        InterfacePtr<ABCInterface> abcInterface(iApplication, UseDefaultIID());

          abcInterface->xyz();

from Main thread no problem but same from background thread give abcInterface point to Null & crash.