Describe a situation where you had to troubleshoot a complex technical issue in a system. What steps did you take to diagnose the issue and what was the outcome?

In a past role, I encountered an issue where the system was failing to authenticate users consistently. I started by reviewing the logs to identify patterns in the failures, and then replicated the issue in a test environment to gather more data. I discovered a configuration error in the authentication module. After correcting the configuration and running tests, the authentication errors were resolved, leading to improved system reliability.