AWS Systems Manager isn't working with my EC2

Does your subnet have a default route to an internet gateway. Have a look in the route table that your subnet is using, and see if you have a default route to an IGW associated with your VPC. If this is not the case, the SSM agent cannot reach the SSM endpoint.

Should you not want to have a route to the public internet, you need to create SSM interface endpoints in your VPC. You can read about how to do that here: https://docs.aws.amazon.com/systems-manager/latest/userguide/setup-create-vpc.html

Hi, Do you have SSM agent installed on EC2?

Hello,

I have had this exact same issue when I run immersion days with customers. Here are a few things to try.

1. If the role is attached and still cant use Session Manager. Go to IAM Dashboard and review you have the following policies applied to your IAM role AmazonSSMManagedInstanceCore.
2. Next thing to check is to make sure your EC2 instance has a Public IP address assigned to it. If it does not have a Public IP address you will need to terminate the instance and redeploy the instance with a Public IP address.
3. Make sure you have created an Internet Gateway and have attached the proper VPC to the Internet Gateway.
4. Make sure your route table has a default route 0.0.0.0/0 pointing to the Internet Gateway
5. If you are still having issues. I recommend to delete your EC2 Instance. And create a new IAM role with policy AmazonSSMManagedInstanceCore and redeploy the EC2 instance. This has worked for a few students.
6. Another thing to note if there are any transit gateways deployed, I would double check all routes and attachments are configured properly as this has also been an issue in the past