AMAZON AWS - Not able to login UBUNTU Server with created users

The AWS Instance is in Ubuntu Server. I can able to login through Ubuntu Server through Ubuntu login (ubuntu@Public DNS value).

I gave the below Host Name in Putty.

ubuntu@ec2-54-67-100-126.us-west-1.compute.amazonaws.com

And also created PPK file from PEM file.(The PPK file name is devsignapi.ppk)

I can able to login to the amazon server with these credentials. And created a user in the Ubuntu Server in the below commands.

   sudo adduser dev1

and set up the password also.

Now i am try to login using the created User dev1. So in Putty, i gave the below Host Name

dev1@ec2-54-67-100-126.us-west-1.compute.amazonaws.com

Using the Dev1 Host Name and devsignapi.ppk file i am trying to login, but i am getting the below errors.

           Using username dev1
           Server refused our key.

Putty Fatal Error

"Disconnected: No Supported Authentication Methods Available(Server Sent:Public Key)"

Sorry i am beginner, i am not able to attach images, because it needs 10 reputation.