A company connects AWS Regions with transit gateways but two EC2 instances in different Regions cannot communicate. A network engineer must troubleshoot the connectivity. Which steps should the engineer take?

The correct approach involves a systematic check of network paths and security configurations. AWS Network Manager Route Analyzer is the primary tool for inspecting routes within transit gateway route tables, which is crucial for inter-Region connectivity. Verifying VPC route tables ensures that traffic is correctly directed to and from the transit gateway within each VPC. Finally, VPC Flow Logs are essential for determining if security groups or network ACLs are blocking traffic, as they capture all IP traffic going to and from network interfaces. Incorrect options: The first option incorrectly suggests using Network Manager Route Analyzer for VPC route tables; while it inspects transit gateway routes, VPC route tables are typically checked separately. The second option incorrectly suggests using AWS Firewall Manager to examine security group or network ACL rules. Firewall Manager is for centralized management of firewalls, not for analyzing traffic logs; VPC Flow Logs are the correct tool for this. The fourth option incorrectly suggests using VPC Reachability Analyzer for transit gateway route tables. Reachability Analyzer is designed for analyzing reachability between resources within a single VPC or across peered VPCs, not primarily for inspecting transit gateway route tables directly.