Getting user prompt while using SSH shell to Ec2 requesting help

Hello All,
I am trying to connect to AWS ec2 ( Linux ) instance through RDM using SSH shell and using keys to authenticate.

I am looking to use ec2-user to directly ssh into the ec2. I tried to use ec2-user@IP as we use in SSh command or Putty but no difference. The same username is prompted.

If I enter the user - ec2-user, it gets connected.

There might be some configurations which I am missing.