When the fiber network shows connected but there's no internet, it means the signal is reaching your modem, but something is going wrong in the translation or distribution process. It could be an issue with the ISP's equipment, your modem, your router, or even your. 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. Why Do Fiber Networks Fail? Despite their robustness, fiber networks can fail due to:. Switch A is on the router end, devices connected to this switch get DHCP leases and can browse the internet without issue. LAN light isn't on on your ONT, PON is the fibre. Despite multiple attempts, the Archer AX6000 v1.