Unable to access ubuntu server

I understand you're having trouble accessing your Ubuntu server named Ubuntu-1. This is a common issue that can occur for various reasons. Here are some steps you can take to troubleshoot and potentially resolve the problem:

1. Check the instance status: Verify that your EC2 instance is in the "running" state and has passed all status checks in the AWS console. Look for "2 of 2 checks passed" in the status.

2. Verify security group settings: Ensure that your EC2 instance's security group allows inbound traffic on port 22 (SSH) from your IP address or from anywhere (0.0.0.0/0) if you're not sure of your IP.

3. Confirm the correct private key: Make sure you're using the correct private key (.pem file) that was associated with the instance when it was launched.

4. Check key permissions: If you're getting a "Server refused our key" error, ensure that the permissions on your private key file are correct. The key should not be accessible to others.

5. Verify the username: For Ubuntu instances, the default username is typically "ubuntu". Double-check that you're using the correct username.

6. Try EC2 Instance Connect: As an alternative, you can attempt to connect using AWS EC2 Instance Connect through the AWS Management Console. This can help determine if the issue is with your local setup or the instance itself.

7. Check system logs: If you can access the system logs through the AWS console, look for any error messages related to SSH connections.

If you've tried these steps and are still unable to connect, you may want to consider using alternative access methods:

1. EC2 Instance Connect: This method allows you to connect to your instance directly from the AWS Management Console, which can be helpful in troubleshooting SSH connection issues.

2. Systems Manager Session Manager: This tool allows you to manage your EC2 instances without the need for open inbound ports or SSH keys. However, it requires some setup, including attaching an IAM role with the necessary permissions to your EC2 instance.

If none of these methods work, you may need to contact AWS support for further assistance. They can provide more detailed diagnostics based on your specific instance configuration.
Sources
Not able to connect Ubuntu server 24.0 using winSCP | AWS re:Post
Access to Linux Instance | AWS re:Post