The next step to troubleshoot the issue after developing and testing a theory is to establish an action plan. This involves identifying the steps needed to implement the solution, estimating the time and resources required, and evaluating the potential risks and impacts of the solution. Documenting the findings and actions, escalating the issue to the management team, or implementing the solution are steps that should be done after establishing an action plan. References: [CompTIA Server+ Certification Exam Objectives], Domain 6.0: Disaster Recovery, Objective 6.2: Explain troubleshooting theory and methodologies.