无法通过SSH连接到AWS权限被拒绝（公钥）

我试图部署我的第一个Web应用程序，并且在尝试SSH进入AWS时遇到了困难。当我输入：

ssh -v -i ec2-myportfolio.pem root@ec2-23-23-165-24.compute-1.amazonaws.com

我收到了“Permission denied(public key)”的错误提示。我查看了一些其他关于stack overflow的响应，例如这个和这个，但是这些解决方案都没有解决我的问题。以下是我遇到的错误。提前感谢您的帮助。

OpenSSH_5.6p1, OpenSSL 0.9.8r 8 Feb 2011
Warning: Identity file ec2-myportfolio.pem not accessible: No such file or directory.
debug1: Reading configuration data /etc/ssh_config
debug1: Applying options for *
debug1: Connecting to ec2-23-23-165-24.compute-1.amazonaws.com [23.23.165.24] port 22.
debug1: Connection established.
debug1: identity file /Users/jonathanschen/.ssh/id_rsa type 1
debug1: identity file /Users/jonathanschen/.ssh/id_rsa-cert type -1
debug1: identity file /Users/jonathanschen/.ssh/id_dsa type -1
debug1: identity file /Users/jonathanschen/.ssh/id_dsa-cert type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.9p1 Debian-5ubuntu1
debug1: match: OpenSSH_5.9p1 Debian-5ubuntu1 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.6
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-ctr hmac-md5 none
debug1: kex: client->server aes128-ctr hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Host 'ec2-23-23-165-24.compute-1.amazonaws.com' is known and matches the RSA host key.
debug1: Found key in /Users/jonathanschen/.ssh/known_hosts:8
debug1: ssh_rsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: Roaming not allowed by server
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey
debug1: Next authentication method: publickey
debug1: Offering RSA public key: /Users/jonathanschen/.ssh/id_rsa
debug1: Authentications that can continue: publickey
debug1: Trying private key: /Users/jonathanschen/.ssh/id_dsa
debug1: No more authentication methods to try.
Permission denied (publickey).
Jonathans-MacBook-Air-2:downloads jonathanschen$