This is one of the most common problems faced by AWS users. If you try to connect to your EC2 instance and get the following error message, it usually indicates a problem with the security group configuration: 

Network error : Connection timed out

The ping command may also fail because the ICMP protocol is not allowed in the inbound connections of the security group rules.

In such situations, ensure that the instance has an elastic IP address and the AWS security group that is associated with the EC2 instance has the required ports open. For example, a Linux instance may require port 22 to be open for SSH access. Similarly, a Windows instance may require port 3389 for remote desktop access. Also, enable ICMP inbound connections.

For a VPC, you must check the routing table of the subnet in which the EC2 instance is running. There must be a route that sends all traffic destined outside the VPC to the internet gateway for the VPC. Also, check the network access control list (ACL) for the subnet. The network ACLs must allow inbound and outbound traffic from your local IP address on the proper port. The default network ACL allows all inbound and outbound traffic.