Circle processes API transfer entities asynchronously after you make the initial create request. If a problem occurs while processing the request, Circle sets the `errorCode` property on the entity. This error can be retrieved either by polling the GET endpoint or from a notification.

## Transfer Error Codes

transfer_failedThe transfer failed due to unknown reasons
transfer_deniedThe transfer was denied by Circle Risk Service, see transfer `riskEvaluation` for more details
blockchain_errorThere was an error processing the transfer on-chain
insufficient_fundsThere was not enough funding to cover the transfer amount