Error in Integrating SRM and ECC

Hi,

I am implementing Transfer of Central Contract from SRM to ECC using Web Services without PI. I have followed all the steps that are mentioned in the document - Transfer of Central Contract from SRM to ECC using Web Services without PI. The issue is when the SAP ECC team is sending Contracts they are getting the below error -

Has any one ever faced this issue ?

Regards.

Somil.