If installed loss exceeds design, reduce connection points, rework poor splices, or use optics with better sensitivity. How to troubleshoot: measure absolute insertion loss with a calibrated source and power meter and compare to the allowed budget. A very common problem is that a connector is not fully engaged - often hard to notice in a crowded patch panel. Or it could be caused by the quality of the connector itself, such as poor end-face geometry that doesn't pass the. Fiber optic adapters are often treated as simple passive interfaces, but their mechanical interaction with the mounting panel plays a critical role in long-term alignment stability and service reliability. Without the proper adapter, signals can degrade or become unstable, which can dramatically decrease the reliability of a network. Fiber link issues can arise for many reasons.