Not able to edit Delta option in DTP

Hi Experts,

Based on Vitual provider the data will be populating to DSO (Standard). In between Multiprovider is there.

I am not able to create Delta DTP it's disable mode. I have tried in multiple ways like..delete the entire target data and try to create new DTP with delta mode

but I am not able to create it. Can you please help me out regarding the same. If you are help in this regards I will be appreciated with points.

Thanks in advance,

Anjan.