Message type: E = Error
Message class:  FKK_ID_SEPA - FICA loc. cross-country SEPA messages 
Message number: 006
Message text: IBAN &1 for SEPA Mandate &2, Partner &3 already used (line number &4)
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The SAP error message FKK_ID_SEPA006 indicates that there is an issue with a SEPA mandate related to an IBAN (International Bank Account Number) that has already been used. This error typically arises in the context of managing SEPA mandates for direct debit transactions in SAP's Financial Accounting (FI) module, particularly in the area of contract accounts receivable and payable (FI-CA).
Cause: The error message is triggered when: An attempt is made to create or process a SEPA mandate using an IBAN that has already been associated with another mandate in the system. The system enforces a uniqueness constraint on the IBAN for SEPA mandates, meaning that each IBAN can only be linked to one mandate at a time.
Solution: To resolve this error, you can take the following steps: Check Existing Mandates: Verify if the IBAN in question is already linked to an existing SEPA mandate. You can do this by checking the mandate records in the
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