EC2 Instance Connect Fails to Connect - Network Configuration Issues or Misconfiguration?

Question

I am trying to connect to my EC2 instance using EC2 Instance Connect, but I keep receiving the following error message:
Failed to connect to your instance
EC2 Instance Connect is unable to connect to your instance. Ensure your instance network settings are configured correctly for EC2 Instance Connect. For more information, see EC2 Instance Connect Prerequisites at https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-instance-connect-prerequisites.html.

Riku_Kobayashi · Answer

Hello.

Please ensure that you meet all the prerequisites listed in the document below as mentioned in the error message.  
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-instance-connect-prerequisites.html

A common problem is that the EC2 security group does not allow SSH connections from EC2 Instance Connect, making it impossible to connect.  
There is a prefix list for EC2 Instance Connect, so please make sure to allow this in the security group's inbound rules.  
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-instance-connect-prerequisites.html#ec2-instance-connect-setup-security-group

EC2 Instance Connect Fails to Connect - Network Configuration Issues or Misconfiguration?

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