SSH authentication failed

SSHLauncher{host='52.14.136.214', port=22, credentialsId='ee9f4ad9-87b6-4d47-bea2-ddc259c55803', jvmOptions='', javaPath='', prefixStartSlaveCmd='', suffixStartSlaveCmd='', launchTimeoutSeconds=210, maxNumRetries=10, retryWaitTime=15, sshHostKeyVerificationStrategy=hudson.plugins.sshslaves.verifiers.KnownHostsFileKeyVerificationStrategy, tcpNoDelay=true, trackCredentials=true}
[11/23/19 17:14:49] [SSH] Opening SSH connection to 52.14.136.214:22.
[11/23/19 17:14:50] [SSH] SSH host key matches key in Known Hosts file. Connection will be allowed.
ERROR: Server rejected the 1 private key(s) for ec2-user (credentialId:ee9f4ad9-87b6-4d47-bea2-ddc259c55803/method:publickey)
ERROR: Failed to authenticate as ec2-user with credential=ee9f4ad9-87b6-4d47-bea2-ddc259c55803
java.io.IOException: Publickey authentication failed.
	at com.trilead.ssh2.auth.AuthenticationManager.authenticatePublicKey(AuthenticationManager.java:302)
	at com.trilead.ssh2.Connection.authenticateWithPublicKey(Connection.java:451)
	at com.cloudbees.jenkins.plugins.sshcredentials.impl.TrileadSSHPublicKeyAuthenticator.doAuthenticate(TrileadSSHPublicKeyAuthenticator.java:109)
	at com.cloudbees.jenkins.plugins.sshcredentials.SSHAuthenticator.authenticate(SSHAuthenticator.java:436)
	at com.cloudbees.jenkins.plugins.sshcredentials.SSHAuthenticator.authenticate(SSHAuthenticator.java:473)
	at hudson.plugins.sshslaves.SSHLauncher.openConnection(SSHLauncher.java:861)
	at hudson.plugins.sshslaves.SSHLauncher$1.call(SSHLauncher.java:425)
	at hudson.plugins.sshslaves.SSHLauncher$1.call(SSHLauncher.java:412)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)
Caused by: java.io.IOException: PEM problem: it is of unknown type
	at com.trilead.ssh2.crypto.PEMDecoder.decodeKeyPair(PEMDecoder.java:500)
	at com.trilead.ssh2.auth.AuthenticationManager.authenticatePublicKey(AuthenticationManager.java:236)
	... 11 more
[11/23/19 17:14:50] [SSH] Authentication failed.
Authentication failed.
[11/23/19 17:14:50] Launch failed - cleaning up connection
[11/23/19 17:14:50] [SSH] Connection closed.