Sales order not found in RRP3

We have a sales order for which ATP should be triggered in the APO system. The confirmed quantity against the sales order in ecc is zero,so the GATP is not taking place. when i check for the sales order in  RRP3, i'm not able to find the order. I checked the IM, the product and the location are there in the IM. Kindly help me with this situation.

Thanks,

Sandeep