ssh - Permission denied (publickey) on Amazon EC2 - ssh

Question

I've been accessing my EC2 instance via SSH on Win7. I'm not trying to ssh it on another pc on Ubuntu 12.04, getting a "Permission denied (publickey)." error. I've been searching for this problem, and tried the following:
Deleted the existing key and created/downloaded a new one on EC2 dashboard.
Placed the new key in my ~/.ssh folder.
Changed the access permissions of the key with this command (Also tried 400):
chmod 600 ~/.ssh/leno.pem
Changed the access permissions of the .ssh folder with this command (Also tried 700):
chmod 755 ~/.ssh
Tried doing this as well:
add-ssh ~/.ssh/leno.pem
No luck. When I try run the following:
ssh -vvv -i ~/.ssh/leno.pem ubuntu#ec2-50-19-199-128.compute-1.amazonaws.com
I get this message:
OpenSSH_5.9p1 Debian-5ubuntu1, OpenSSL 1.0.1 14 Mar 2012
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to ec2-50-19-199-128.compute-1.amazonaws.com [50.19.199.128] port 22.
debug1: Connection established.
debug3: Incorrect RSA1 identifier
debug3: Could not load "/home/murat/.ssh/leno.pem" as a RSA1 public key
debug1: identity file /home/murat/.ssh/leno.pem type -1
debug1: identity file /home/murat/.ssh/leno.pem-cert type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.5p1 Debian-4ubuntu6
debug1: match: OpenSSH_5.5p1 Debian-4ubuntu6 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.9p1 Debian-5ubuntu1
debug2: fd 3 setting O_NONBLOCK
debug3: load_hostkeys: loading entries for host "ec2-50-19-199-128.compute-1.amazonaws.com" from file "/home/murat/.ssh/known_hosts"
debug3: load_hostkeys: found key type RSA in file /home/murat/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys
debug3: order_hostkeyalgs: prefer hostkeyalgs: ssh-rsa-cert-v01#openssh.com,ssh-rsa-cert-v00#openssh.com,ssh-rsa
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit: ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa-cert-v01#openssh.com,ssh-rsa-cert-v00#openssh.com,ssh-rsa,ecdsa-sha2-nistp256-cert-v01#openssh.com,ecdsa-sha2-nistp384-cert-v01#openssh.com,ecdsa-sha2-nistp521-cert-v01#openssh.com,ssh-dss-cert-v01#openssh.com,ssh-dss-cert-v00#openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-dss
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc#lysator.liu.se
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc#lysator.liu.se
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64#openssh.com,hmac-sha2-256,hmac-sha2-256-96,hmac-sha2-512,hmac-sha2-512-96,hmac-ripemd160,hmac-ripemd160#openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64#openssh.com,hmac-sha2-256,hmac-sha2-256-96,hmac-sha2-512,hmac-sha2-512-96,hmac-ripemd160,hmac-ripemd160#openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib#openssh.com,zlib
debug2: kex_parse_kexinit: none,zlib#openssh.com,zlib
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc#lysator.liu.se
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc#lysator.liu.se
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64#openssh.com,hmac-ripemd160,hmac-ripemd160#openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64#openssh.com,hmac-ripemd160,hmac-ripemd160#openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib#openssh.com
debug2: kex_parse_kexinit: none,zlib#openssh.com
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: mac_setup: found hmac-md5
debug1: kex: server->client aes128-ctr hmac-md5 none
debug2: mac_setup: found hmac-md5
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
debug2: dh_gen_key: priv key bits set: 142/256
debug2: bits set: 534/1024
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Server host key: RSA c4:de:26:09:64:6f:7c:48:6b:2b:ef:8c:c5:b7:cc:1f
debug3: load_hostkeys: loading entries for host "ec2-50-19-199-128.compute-1.amazonaws.com" from file "/home/murat/.ssh/known_hosts"
debug3: load_hostkeys: found key type RSA in file /home/murat/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys
debug3: load_hostkeys: loading entries for host "50.19.199.128" from file "/home/murat/.ssh/known_hosts"
debug3: load_hostkeys: found key type RSA in file /home/murat/.ssh/known_hosts:2
debug3: load_hostkeys: loaded 1 keys
debug1: Host 'ec2-50-19-199-128.compute-1.amazonaws.com' is known and matches the RSA host key.
debug1: Found key in /home/murat/.ssh/known_hosts:1
debug2: bits set: 514/1024
debug1: ssh_rsa_verify: signature correct
debug2: kex_derive_keys
debug2: set_newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug2: set_newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: Roaming not allowed by server
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug2: key: leno.pem (0x7feb7db9aa10)
debug2: key: /home/murat/.ssh/leno.pem ((nil))
debug1: Authentications that can continue: publickey
debug3: start over, passed a different list publickey
debug3: preferred gssapi-keyex,gssapi-with-mic,publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Offering RSA public key: leno.pem
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: Authentications that can continue: publickey
debug1: Trying private key: /home/murat/.ssh/leno.pem
debug1: read PEM private key done: type RSA
debug3: sign_and_send_pubkey: RSA ab:3a:89:be:34:43:5a:40:5f:8a:0c:ba:5d:33:bd:cb
debug2: we sent a publickey packet, wait for reply
debug1: Authentications that can continue: publickey
debug2: we did not send a packet, disable method
debug1: No more authentication methods to try.
Permission denied (publickey).
How can I access my EC2 insance via ssh? What am I doing wrong?

Answer 1

When you do this:
Deleted the existing key and created/downloaded a new one on EC2
dashboard.
You do not change the key on existing instances. All you do is create a new key that could be assigned to newly launched instances.
You are connecting to the instance and it is responding. When you get this error it means that either the user you are connecting to does not exist, or your public key is not installed in that users authorized_keys file.

Answer 2

I resolved this problem by following below steps:
1- Grant permission to you ssh-key.pem with this command:
chmod 400 ssh-key.pem
2- Use command ssh-keygen to get publicKey and copy it:
ssh-keygen -y -f ssh-key.pem
3- Open your AWS console and select your instance and click on connect button.
4- Click on EC2 Instance connect and click on button connect to open remote terminal.
5- After that execute command:
vi ~/.ssh/authorized_keys
6- Change server key by your local generated key on step2.
7- Save your file.
8- open your local terminal.
9- Use this command to connect:
ssh -i ssh-key.pem ubuntu#yourIpAdress

Answer 3

I got this error:
Permission denied (publickey,gssapi-keyex,gssapi-with-mic).
The resolution was adding the ec2-user (default user) before the public dns.