Wmtndeliverydeliver sending no data to receiving service

In my TN processing service, I am passing on bizdoc to wm.tn.delivery:deliver service which is successfully invoking the receiving IS service however I don’t see any thing in receiving service input pipeline. I have confirmed that before calling ‘deliver’ service, the bizdoc/Content fields contains the xml data.

I wonder if someone else encountered the same problem and resolved it.