AWS Certified Advanced Networking - Specialty ANS-C01 — Question 44

A company has hundreds of Amazon EC2 instances that are running in two production VPCs across all Availability Zones in the us-east-1 Region. The production VPCs are named VPC A and VPC B. A new security regulation requires all traffic between production VPCs to be inspected before the traffic is routed to its final destination. The company deploys a new shared VPC that contains a stateful firewall appliance and a transit gateway with a VPC attachment across all VPCs to route traffic between VPC A and VPC B through the firewall appliance for inspection. During testing, the company notices that the transit gateway is dropping the traffic whenever the traffic is between two Availability Zones. What should a network engineer do to fix this issue with the LEAST management overhead?