SAP Message 06026 - Please enter material number or account assignment category

Diagnosis
You have entered neither thematerial number nor the account assignment category
in the item. An item representing a material without amaster record (i.e. nomaterial number is specified) or a service must have an accountassignment category.

Procedure
Enter a valid material number.
If you wish to procure a material without a master record or a service,enter a suitable account assignment category for the item.