The Data Services Request contains SystemQueryOptions that are not allowed for this Request Type

Hi Team,

I'm trying to post a sales order through ODATA service but it's giving below error

'The Data Services Request contains SystemQueryOptions that are not allowed for this Request Type' .

URL:

/sap/opu/odata/SAP/Z_API_SALES_ORDER_SRV/A_SalesOrderSet?$expand=A_SalesOrderItemSet

Same has been working for GET operation. I have used association and deep structure to post a sales order with multiple line items.

Can you please suggest how to fix it?

Thanks in advance,

Girdhari Mondal