Missing data: Provision account...while saving Sales Order.

Hello Experts,

I am facing below message while creating the sales order.

While saving the sales order system reach to Incompletion log window and ask to maintain "Provision account" once I click it system reach me on condition tab and give the message "Missing data: Provision account"

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Missing data: Provision account

Message no. VU019

Diagnosis

The system checked the document for completion and found some missing data.

System Response

You cannot continue processing.

Procedure

Enter the missing data.

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Please guide me to resolve this issue.

Thanks,