billing budget and server issue

Hi, on your connection issue to the EC2 instance,

I strongly recommend to read https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/TroubleshootingInstancesConnecting.html

I strongly suggest to start connecting with Instance Connect from the console: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/Connect-using-EC2-Instance-Connect.html (please, respect prereqs)

Then you can try connecting with SSH (Linux) or RDP (Windows) from your laptop.

Explicit ping requires that your security groups allow for ICMP trafic: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/security-group-rules-reference.html#sg-rules-ping

The reason for the ping not succeeding is due to the EC2 security group and VPC network ACLs, as others have explained.
If ICMP is set to inbound rules as per the following document, I believe the ping will succeed.
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/security-group-rules-reference.html#sg-rules-ping

As for the fee, I thought it exceeded the limit of the free quota.
The one-year free slots are available for the following documents.
https://aws.amazon.com/free/?nc1=h_ls&all-free-tier.sort-by=item.additionalFields.SortRank&all-free-tier.sort-order=asc&awsf.Free%20Tier%20Types=*all&awsf.Free%20Tier%20Categories=*all

You can check the services for which you are being charged by using this document.
https://repost.aws/knowledge-center/check-for-active-resources

thank you two, I read your links and find out the answers. have a good day.