Ping from on-premise to all my EC2 instance has packet loss

I would start by investigating the connection from on-prem to AWS. Below are two guides that can help to troubleshoot the packet loss. How do I troubleshoot packet loss on my VPN connection? https://repost.aws/knowledge-center/troubleshoot-vpn-packet-loss How can I troubleshoot packet loss for my Direct Connect connection? https://repost.aws/knowledge-center/direct-connect-packet-loss

Hi, this very probably comes from the fact that your different EC2 instances are protected by different security groups: one allowing ICMP (ping) and the other not. So, please, identify those 2 sec groups and align them for ICMP.

See details to allow ping (specifically): https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/security-group-rules-reference.html#sg-rules-ping.

If groups are same, the second possible cause is absence of public IP for the failing one. See https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-instance-addressing.html#concepts-public-addresses to check if you have one for your instance and how to add it if not.