This is a unique capture / sale id yes, but not the transaction-id the buyer sees when he logs into his paypal account. As the thread starter said, this buyer transaction-id cannot be found anywhere. I am facing the same issue at integrating and for future customer support he will ask "my transactioncode is '1245ABCD" and we cannot do anything with this in support. Problem Further the "invoice-id" is identical for the transaction which can have multiple captures! The buyer can search by this invoice-id and will find multiple "transactoins / captures". Here a screenshot from the sandbox buyer account and those two captures belong to one single payment-id. Its actually a guessing game which "capture-id" is which byuer "transaction".
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