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!


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.


PuTTY does not natively support the private key format (.pem) generated by Amazon EC2. PuTTY has a tool named PuTTYgen, which can convert keys to the required PuTTY format (.ppk). You must convert your private key into this format (.ppk) before attempting to connect to your instance using PuTTY.

The steps how to perform this are described here: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/putty.html

This solved the problem.