amp sshj error

Cannot establish ssh connection to dev1 @ SshMachineLocation[54.220.131.48:dev1@ec2-54-220-131-48.eu-west-1.compute.amazonaws.com/54.220.131.48:22(id=flw81h8dav)] (Exhausted available authentication methods). Ensure that passwordless and passphraseless ssh access is enabled using standard keys from ~/.ssh or as configured in brooklyn.properties. Check that the target host is accessible, that credentials are correct (location and permissions if using a key), that the SFTP subsystem is available on the remote side, and that there is sufficient random noise in /dev/random on both ends. To debug less common causes, see the original error in the trace or log, and/or enable 'net.schmizz' (sshj) logging.: SshException: (dev1@ec2-54-220-131-48.eu-west-1.compute.amazonaws.com:22) failed to connect: (dev1@ec2-54-220-131-48.eu-west-1.compute.amazonaws.com:22) (dev1@ec2-54-220-131-48.eu-west-1.compute.amazonaws.com:22) error acquiring {hostAndPort=ec2-54-220-131-48.eu-west-1.compute.amazonaws.com:22, user=dev1, ssh=963338482, password=xxxxxx, privateKeyFile=/home/amp/.ssh/id_rsa, privateKey=xxxxxx, connectTimeout=0, sessionTimeout=0} (attempt 4/4, in time 2.89s/2m); out of retries: Exhausted available authentication methods