Message type: E = Error
Message class:  FKKEXC - Message Class for External Payments 
Message number: 166
Message text: Payment &1 of branch/cash desk &2/&3 is already reversed
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The SAP error message FKKEXC166 indicates that a payment has already been reversed for a specific branch or cash desk. This error typically occurs in the context of the SAP Contract Accounts Receivable and Payable (FI-CA) module, which is used for managing customer accounts and payments.
Cause: The error arises when you attempt to reverse a payment that has already been reversed. This can happen due to: Duplicate Reversal Attempt: The payment has already been reversed, and you are trying to reverse it again. Incorrect Payment Reference: The payment reference or details you are using to reverse may not match the original payment. System
Configuration Issues: There may be issues with the configuration of the cash desk or branch settings in the system.
Solution: To resolve this error, you can take the following steps: Check Payment History: Review the payment history for the specific branch/cash desk to confirm whether the payment has indeed been reversed. You can do this
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