Why I can't connect through SSH to my EC2 instance? Permission denied

Question

I created EC2 within my VPC that has a public subnet I used standard security group settings

When I try to SSH

ec2_user@3.123.36.129: Permission denied (publickey,gssapi-keyex,gssapi-with-mic).

My route table routes(I have Internet Gateway)

Why did I got denied permission? What should I check regarding my subnet?

Answer 1

Change the permissions of the .pem file so only the root user can read it hope might this work in your case as most of the time we have to give permission to pem file.

sudo chmod 400 ~/.ssh/ec2private.pem