Unable to Connect to EC2 Instance thru SSH

Hello AlvinCheung,

I have checked your instance and I can see that it is healthy with 2/2 successful health checks. Also, the access list and route table are correctly configured.

Having said that, I was able to reach the server on port 80 from my end as it is open to the world but not via the port 22 because traffic is allowed only from 1 IP.

To make sure that the allowed IP belongs to you please update the security group rule for port 22 and choose as "source", "My IP". Then please try to SSH to the instance again. Additionally, for your reference I would like to share this useful link too. https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/TroubleshootingInstancesConnecting.html

In regards the ping failure, please note that there is no ICMP rule configured at the security group to allow ICMP messages. Therefore, if you want to ping the server you will have to create a new rule as per your requirements.

Lastly, in order to be able to use the Session manage please make sure to meet the prerequisites as per the document below. By looking at the instance I can see that you did not attach an instance profile.
https://docs.aws.amazon.com/systems-manager/latest/userguide/session-manager-getting-started.html

If the issue persists please let me know what error message PuTTY returns and remember to hide any public IP addresses.

Thank you,
VasosAWS

Thanks! The problem is solved.