EC2 Instance Error (Failed in Instance reachability check )

Question

Hi,

My EC2 instance is suddenly stopped connecting through SSH and **Instance reachability check also failed.**

![Enter image description here](/media/postImages/original/IMMIcPE1zCSLOz_nq1OVKpqg)

When I tried to connect to my EC2 instance, I am getting below error message

**"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."**

![Enter image description here](/media/postImages/original/IMdmhLjCB-S42NQZDzGdYNeA)

In have checked all the necessary steps mentioned in the post: **https://repost.aws/questions/QUXaZXuLx9QAKGa1o5vdlfkw/ec2-instance-error-failed-to-connect**

I am not able to get the system log also. Please help me to fix this issue.

Mrityunjay Singh · Answer

This generally indicates a network connectivity issue.
kindly validate the - SG rules, NACLs, Route Table, subnet, IGW, VPC configurations etc to ensure there are no network configuration issues.
Are there any other EC2 instances with exactly the same configuration and in same subnet facing this issue? 
Are there any specific errors on cloudwatch instance logs (if enabled)?

There could be several other reasons for this but  you would have to go on a elimination approach to resolve it.
Refer the guidance in below documentations for further troubleshooting - 
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/TroubleshootingInstances.html#system-log-errors-linux 
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/monitoring-system-instance-status-check.html#:~:text=a%20pass%20status.-,Instance%20status%20checks,-Instance%20status%20checks

EC2 Instance Error (Failed in Instance reachability check )

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