Copy files from private EC2 instance to local machine

Hi,

I have a requirement of copying files from private EC2 instance to my local machine. I have port forwarded a EC2 instance to local using below command.

aws ssm start-session
--target instance-id
--document-name AWS-StartPortForwardingSession
--parameters '{"portNumber":["22"], "localPortNumber":["2222"]}'

Now is there a way to copy files from EC2machine to local machine without passing PEM keys. I have tried it but getting error

scp -P 2222 ec2-user@localhost:/var/log/yumlog /home/user ec2-user@localhost: Permission denied (publickey,gssapi-keyex,gssapi-with-mic).

Can any one guide to copy the files.