Amazon ssh permission denied (public key) with error message - amazon-web-services

Question

I just set up my AWS Deep Learning instance and paired it to a new key pairs file I created.
However, when I try to ssh with the following command:
ssh -v -i /Users/username/aws-deep-learning-ami.pem ubuntu#INSTANCE_IP.compute.amazonaws.com
I get the rather long error message: permission denied (public key).
Printing the details with -v shows this:
OpenSSH_7.2p2, OpenSSL 1.0.2k 26 Jan 2017
debug1: Reading configuration data /etc/ssh_config
debug1: /etc/ssh_config line 57: Applying options for *.com
debug1: /etc/ssh_config line 67: Applying options for *.*
debug1: /etc/ssh_config line 77: Applying options for *
debug1: Connecting to instance.amazonaws.com [ip] port 22.
debug1: using TCP window size of 65536 / 65536
debug1: Connection established.
debug1: key_load_private_cert: No such file or directory
debug1: key_load_cert: No such file or directory
debug1: key_load_public: No such file or directory
debug1: identity file /Users/username/aws-deep-learning-ami.pem type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/username/aws-deep-learning-ami.pem-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/username/.ssh/id_rsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/username/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/username/.ssh/localhost/id_rsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/username/.ssh/localhost/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/username/.ssh/clusterhost/id_rsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/username/.ssh/clusterhost/id_rsa-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.2
debug1: Remote protocol version 2.0, remote software version OpenSSH_6.6.1
debug1: match: OpenSSH_6.6.1 pat OpenSSH_6.6.1* compat 0x04000000
debug1: Authenticating to instance as 'ubuntu'
debug1: Miscellaneous failure (see text)
No credentials cache file found
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: algorithm: key
debug1: kex: host key algorithm: key
debug1: kex: server->client cipher: key MAC: <implicit> compression: none
debug1: kex: client->server cipher: key MAC: <implicit> compression: none
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: key
debug1: Host 'instance.compute.amazonaws.com' is known and matches the ECDSA host key.
debug1: Found key in /Users/username/.ssh/known_hosts:7
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey
debug1: Next authentication method: publickey
debug1: Offering ECDSA public key: publickey
debug1: Authentications that can continue: publickey
debug1: Offering ECDSA-CERT public key: corp/normal
debug1: Authentications that can continue: publickey
debug1: Trying private key: /Users/username/aws-deep-learning-ami.pem
debug1: Authentications that can continue: publickey
debug1: Trying private key: /Users/username/.ssh/id_rsa
debug1: Trying private key: /Users/username/.ssh/localhost/id_rsa
debug1: Trying private key: /Users/username/.ssh/clusterhost/id_rsa
debug1: No more authentication methods to try.
Permission denied (publickey).

Answer 1

In general, default usernames are:
Amazon Linux uses ec2-user
Ubuntu AMIs use ubuntu
Amazon EMR uses hadoop

Answer 2

As stdunbar mentioned I had to use ec2-user instead of ubuntu