Unable to connect to the AWS EC2 instance using any method

Question

I am running the free t2.micro instance. Since last night I have been unable to connect to the instance using any method. I've tried using Termius, Terminal, and the built-in console, but none work. My dashboard says the server is online and connectable though. I can't ask for support directly because of the aforementioned free tier. What should I do? I did reboot and stop & restart my instance but nothing works.

Nitin Bhadauria · Accepted Answer

Based on this msg "EC2 Instance Connect is unable to connect to your instance" it look like there is a network misconfiguration of hardware failure. Can you confirm following:

1. Check is system Status check is "2/2 checks passed" 
2. Check if you can telnet 22 port of server. If telnet works share the output of "ssh -v -i key.pem ubuntu@SERVER.IP"
3. Check if 22 port is not blocked. use nmap like this "nmap SERVER.IP -Pn -p 22"

myronix88 · Answer

Check if you have internet gateway attached to a VPC, without it you will not be able to connect to EC2 instance.

Mikel Del Tio · Answer

Hi,

There could be [many reasons](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/TroubleshootingInstancesConnecting.html) why you can't access your EC2 instance, could you attach the error message so we can help you more precisely?

On the other hand, I recommend you take a look at the following [Knowdlege Center article](https://repost.aws/knowledge-center/ec2-linux-ssh-troubleshooting), specially to the [Troubleshoot common errors](https://repost.aws/knowledge-center/ec2-linux-ssh-troubleshooting) sections,  which explains how to troubleshoot issues to connect to an Amazon EC2 Linux instance using SSH, based on your error message.

MikeLim · Answer

As per your comments, you installed UFW and only allow HTTP/HTTPS (Nginx) incoming. You did not allow incoming SSH at port 22.
```
i did install ufw and entered following command

sudo apt-get install ufw -y
sudo ufw default deny incoming
sudo ufw default allow outgoing
sudo ufw allow 'Nginx HTTPS'
sudo ufw allow 'Nginx Full'
sudo ufw enable -y
```

If you are running a OS (operating system) with SSM agent installed, you may be able to connect via [SSM Session Manager](https://aws.amazon.com/blogs/aws/new-session-manager/). Try the steps at [Connect to your Linux instance using Session Manager](https://catalog.workshops.aws/general-immersionday/en-US/basic-modules/10-ec2/ec2-linux/3-ec2-1). You may need to reboot your EC2 instance for session manager to work.

Unable to connect to the AWS EC2 instance using any method

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