The fastest way to restore the service after deploying a new application release to the green stack of a blue-green infrastructure model and making the green stack primary is to failback to the blue stack. Failing back means switching back to the previous version of the application that is running on the blue stack, which is still available and functional. This will minimize the downtime and impact on the users, while allowing the systems administrator to troubleshoot and fix the issues on the green stack. Reference: [CompTIA Cloud+ Certification Exam Objectives], Domain 4.0 Troubleshooting, Objective 4.4 Given a scenario, troubleshoot deployment issues.