If you're experiencing issues with booting a new instance that was created from a snapshot in AWS EC2 or Lightsail, there are several potential reasons for this. Here's a step-by-step troubleshooting guide:

AWS EC2:

1. Check Security Group and Firewall Rules:

   • Ensure that the security group associated with the new instance allows inbound traffic on the necessary ports. Also, confirm that network ACLs and firewall rules are not blocking essential connections.

2. Review Instance Status and System Logs:

   • Log in to the AWS Management Console, go to the EC2 Dashboard, and check the status of the instance. Review system logs, including the instance console output, for any error messages or warnings.

3. Verify Key Pair:

   • If your original instance used a specific key pair for SSH access, make sure you're using the correct key pair when trying to access the new instance.

4. Check the Volume State:

   • Ensure that the EBS volume attached to the instance is in an "available" state and properly connected.

5. AMI Compatibility:

   • Verify that the AMI (Amazon Machine Image) used to create the snapshot is compatible with the instance type and region you're trying to launch the new instance in.

6. Instance Type and Architecture:

   • Confirm that the instance type and architecture (32-bit or 64-bit) of the new instance are compatible with the snapshot.

7. Check for Pending Actions:

   • Check if there are any pending actions on the instance or its associated resources, such as volumes or snapshots.

8. Inspect IAM Roles and Policies:

   • Ensure that the IAM roles and policies associated with the instance allow it to access necessary resources and services.

9. Verify VPC and Subnet Settings:

   • Ensure that the VPC and subnet settings for the new instance are correctly configured.

Lightsail:

1. Review Instance Status and Logs:

   • Log in to the Lightsail console and check the status of the instance. Review system logs for any error messages or warnings.

2. Check Networking Configuration:

   • Ensure that the networking configuration (including firewall rules) allows inbound traffic on necessary ports.

3. Verify Snapshots:

   • Double-check that the snapshot you used to create the new instance is in a healthy state and hasn't been corrupted.

4. Check Key Pair:

   • Ensure you're using the correct key pair for SSH access to the new instance.

5. Verify Instance Plan:

   • Make sure that the Lightsail plan you're using supports the instance type and resources you're trying to create.

6. Review Static IP and DNS Settings:

   • Ensure that any static IPs and DNS configurations associated with the instance are correctly set up.

7. Inspect Firewall Settings:

   • Confirm that firewall settings in the Lightsail console are not blocking necessary connections.

8. Check for Billing Issues:

   • Verify that your Lightsail account is in good standing and that there are no billing or payment issues that could be affecting instance launches.

If you've gone through these steps and are still experiencing issues, consider reaching out to AWS Support (for EC2) or Lightsail Support for further assistance. They have access to additional tools and resources that can help troubleshoot specific issues with your instances.