Dear Prasant,
Please check if the materials are reserved or not, for this go to MMBE and find the reservation status of material. If there is no reservations then check VBBE table in SE16 for any open orders for that material. If nothing is working then go to MD04 and give your material and MRP Area and then Plant and execute, check for safety stock quantity if this is blocked by the MRP. Please check and confirm.
Thanks,
Kumar