Diagnosis
SAP Credit Management is active.
The "Simple Credit Limit Check", that is, the characteristics
,,'A' (Execute credit limit check and warning)
,,'B' (Execute credit limit check and error)
,,'C' (Execute credit limit check and delivery block)
maintained in Customizing "Assign Sales- and Delivery Documents"(transaction OVAK), are not supported.

Procedure
In the Customizing tree, go to
Financial Supply Chain Management --> Credit Management -->Integration with Accounte Receivable Accounting and Sales --> I
ntegration with Sales --> Assign Sales- and Delivery Documents
and maintain the credit limit check for order types. Use characteristic'D' (Credit Management: Automatic credit check).