Password for the instance

Hello.

By default, EC2 instances cannot connect via SSH using password authentication.
You will need to connect using an SSH key pair.
https://repost.aws/knowledge-center/ec2-ssh-best-practices

If the EC2 OS is Windows Server, there is an administrator password, so please check it using the steps in the document below.
https://repost.aws/knowledge-center/retrieve-windows-admin-password