No while calling the save method from my extension i am getting this error.my order as well as orderItem in my vf page are not getting inserted and this error is poping up.
Looks like there could be other validation rules or triggers that could be running you need to check if there are any and see-through that the required fields are not empty while inserting the record.
Let me know if it helps you and close your query by marking it as solved so that it can help others in the future.
I assume you are seeing this error in a test class? If so, as the error suggests, you need to insert a pricebookEntry
Assign the price book entry to the OrderItem.
Reference:https://salesforce.stackexchange.com/questions/274205/writing-test-class-for-order-activate-error-required-fields-are-missing-pric
Hope this helps you. Please mark this answer as best so that others facing the same issue will find this information useful. Thank you
Looks like there could be other validation rules or triggers that could be running you need to check if there are any and see-through that the required fields are not empty while inserting the record.
Let me know if it helps you and close your query by marking it as solved so that it can help others in the future.
Thanks.