Pricing Error: Mandatory pricing PR00 is missing

Hi, when I enter the items in the sales order, it says "Pricing Error: Mandatory pricing PR00 is missing"

I also entered PR00 manually, but still gives the same error. I assigned PR00 for the materials through vk11, still not working. How do I fix it?

I would appreciate stp-by-step procedure.

Rewards will be given.

Thanks.