The solution is to unplug the fiber and reinsert it into the SFP module interface until a “click” sound is heard, indicating the fiber connector and SFP module are properly connected. Before troubleshooting the issue, please look at our 16 tips for troubleshooting your optical transceiver connections. Check compatibility between the optical module and switch Most switch brands have specific compatibility requirements. Small Form-factor Pluggable modules (SFP module) are the workhorses of modern network connectivity, enabling flexible fiber optic or copper links between switches, routers, firewalls, and servers. These faults can affect network stability and, in severe cases, cause network interruptions, resulting in losses.