Check Fiber Cables : Look for visible damage, sharp bends, or loose connectors. Replace compromised cables. Clean Connectors : Use lint-free wipes and isopropyl alcohol to remove dust or oil. When issues like signal loss, slow speeds, or intermittent connectivity arise, systematic troubleshooting is key. This guide will walk you through diagnosing and resolving common fiber network issues efficiently. I was given a new gateway modem/router. Typical causes include reversed Tx/Rx polarity, severe fiber optic connector contamination, incompatible. This morning my ISP upgraded my Internet connection from a standard coaxial cable and Cisco modem to a fiber optic cable and Hitron modem Model Name NOVA-2004. Despite multiple attempts, the Archer AX6000 v1.