Delivery from plant XXXX for material xxx is not possible for STO

Dear Experts,

I could not able to create outbound delivery for inter/intra sto as system gives error as "Delivery from plant XXXX for Material X is not possible".

I've configured relevant sales area, delivery type for supplying plant, and document type/supplying plant/receiving plant combinations. I'm not sure which makes this error. Could someone please help.