PuTTY does not natively support the .pem format used by AWS. You must use PuTTYgen to convert your .pem file into a .ppk file before initiating the connection.

Steps to Connect

1
Open PuTTYgen and click 'Load' to select your .pem file.
2
Click 'Save private key' to generate and save the .ppk file.
3
Open PuTTY and navigate to Connection > SSH > Auth > Credentials.
4
Browse for your .ppk file in the 'Private key file for authentication' field.
5
Return to Session, enter the instance public IP, and click 'Open'.