Duplicate Receipt Error in Manage Lockbox Transmission

In the Manage Lockbox Transmission sheet, two receipts for the same customer are encountering the error: “This receipt number already exists for this customer and amount.”Upon reviewing the Lockbox File, I found six receipts for this customer with the same receipt number (01783). Four have already been created successfully in the application with amounts of 76, 114, 228, and 152, respectively.The remaining two receipts, both amounting to 190, are stuck. However, I could not find any existing receipt with number 01783 and amount 190 in the system.Could anyone of you who has worked on Lockbox, please clarify why these two receipts are triggering the duplicate receipt error? Is it due to both receipts having the same amount and receipt number?