Message type: E = Error
Message class:  FKK_SEPA - FI-CA: SEPA Mandate Management 
Message number: 018
Message text: Bank &1 has IBAN &2, no suitable mandate, e.g. has mandate &3 IBAN &4
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The SAP error message FKK_SEPA018 indicates that there is an issue with the SEPA (Single Euro Payments Area) mandate related to a bank account. Specifically, the error message states that the specified bank (Bank &1) has an IBAN (International Bank Account Number) &2, but there is no suitable mandate available. It also mentions that there is an existing mandate (mandate &3) associated with a different IBAN (&4).
Cause: Missing Mandate: The primary cause of this error is that there is no valid SEPA mandate for the specified IBAN. A mandate is required for direct debit transactions, and it must be linked to the correct bank account. Incorrect IBAN: The IBAN provided may not match the one associated with the existing mandate. This can happen if the customer has multiple bank accounts or if there was a data entry error. Inactive Mandate: The mandate might be inactive or expired, which means it cannot be used
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