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Third-party request failed [ERROR CODE:620;ERROR MESSAGE:TxnID Cannot Be Linked
ERROR DETAIL:TxnID Cannot Be Linked : <XXXX>;MORE ERROR DETAIL:Payment.Line.LinkedTxn.TxnId ]
This error occurs when the customer record associated with the transaction at the time of invoice creation(in QBO) is different from the customer record found during payment creation (in QBO).
To resolve this error, navigate to your Quickbooks account and share the required customer ID(present in the URL of the customer page) to support.