Preventive Measures Always keep dust caps installed when ports are unused. Inspect fiber end faces before every connection. Fiber connectors play an important role in maintaining. This article will help you understand various warning signs for common faults, suggest practical troubleshooting steps, and share preventive inspections and maintenance, so you can do your due diligence in keeping your network safe with high availability. Therefore, understanding common failure causes and. Why Optical Modules Fail After Deployment — And How to Avoid It? Optical modules (SFP, SFP+, QSFP, QSFP28, etc. ) are designed for high reliability in modern networks. Yet in real-world deployments, many data centers, ISPs, and enterprise networks still experience unexpected link failures after. Causes include manufacturing defects, excessive operating temperature, voltage spikes, or simply reaching end-of-life. Symptoms: Gradual increase in Bit Error Rate (BER), reduced optical power output (Tx), decreased receiver sensitivity (Rx), complete loss of light transmission or reception.