Receiver SFTP Channel Error

Hello Team,

   I am using SAP PI 7.11. SP12. When I am trying to send the data to receiver SFTP. Getting the below error :

"Message processing failed. Cause: javax.resource.ResourceException: java.lang.UnsupportedOperationException: received authentication request from server which could not be processed: destination=xxx@xxxxxx; name=; instruction=prompt=Password: "

   Could you please provide your valuable inputs.

Thanks

Ravi