AWS - Disconnected : No supported authentication methods available (server sent :publickey)

I had the same problem, by accident mistake. I'll share it here, in case someone may have made the same mistake.

Basic steps, as others described.

  1. Download putty and puttygen, or the putty package and install it.
  2. Get the .pem file from your AWS EC2 instance.
  3. Use puttygen to convert the .pem file so that you'll have a private key --- mistake happened here. I chose "Conversions" tab from PuttyGen, and load my .pem file. After loading pem file, here DO NOT hit "Generate", instead directly "Save private key". That's the key you need. If you click Generate, you'll have a totally different pair of keys.
  4. In putty, use [email protected], and load the private key at SSH/Auth

Good luck!


Comprehensive answer is here: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/putty.html

Your problem can be related to incorrect login which varies depending on AMIs. Use following logins on following AMIs:

  • ubuntu or root on ubuntu AMIs
  • ec2-user on Amazon Linux AMI
  • centos on Centos AMI
  • debian or root on Debian AMIs
  • ec2-user or fedora on Fedora
  • ec2-user or root on: RHEL AMI, SUSE AMI, other ones.

If you are using OS:

  • Windows - get PEM key from AWS website and generate PPK file using PuttyGen. Then use Putty to use the PPK (select it using left-column: Connection->SSH->Auth: Private key for authorization)
  • Linux - run: ssh -i your-ssh-key.pem login@IP-or-DNS

Good luck.


There is another cause that would impact a previously working system. I re-created my instances (using AWS OpsWorks) to use Amazon Linux instead of Ubuntu, and received this error after doing so. Switching to use "ec2-user" as the username instead of "ubuntu" resolved the issue for me.


You will also receive "Disconnected : No supported authentication methods available (server sent :publickey)" when you have a correct Linux user but you haven't created the file .ssh/authorized_keys and saved the public key as indicated in Managing User Accounts on Your Linux Instance