There’re could be some reason, but the common reason is if you input the stock/ valuated item in the material, system should not asked you the acc. asignment.
The acc assignment cat means system needs to directly define how to allocate the costs for this material.
How to keep mandatory for subcontracting Purchase requisitions to be saved for K & L? It should not get saved without account assignment as K and item category as L. Pl guide
If you are unable to create a purchase order due to discrepancies in the material master data, I recommend that you validate and update the material master records to ensure that the procurement processes are accurate. If the material document is not getting posted after the goods receipt, you can verify the goods receipt document and check for any missing mandatory fields. You might also want to review the system configurations for the proper goods movement settings. In cases where the pricing conditions are not calculating correctly in purchase orders, you should evaluate the condition records, pricing procedures, and master data to identify and resolve pricing discrepancies. This will ensure that your procurement transactions are accurate.
SAP Materials Management (MM) is the main module that handles procurement processes, inventory management, and material valuation. Common issues include inventory discrepancies, order errors, and supplier management issues. Resolving these issues quickly is critical to ensuring uninterrupted supply chain operations and accurate financial reporting.