Troubleshoot Full Fibre Broadband Problems
FTTP Not Working Properly? Here’s how to troubleshoot before contacting our Support Team
Full Fibre (FTTP) is fast, reliable, and brilliant — until something doesn’t quite work as expected.
If you’re experiencing slow speeds, dropouts, or a complete loss of connection, there are a few simple checks you can carry out before raising a fault.
Following the steps below helps us quickly identify whether the issue is Wi-Fi, router-related, or the fibre connection itself — saving time and getting you back online faster.
1. Run a Speed Test (Wired and Wireless)
The first step is to rule out Wi-Fi issues.
Do both of the following:
- Connect a laptop or PC directly to your router using an ethernet cable and run a speed test.
- Run the same test over Wi-Fi
If the wired speeds are close to what you expect but Wi-Fi is slow or unstable, the issue is likely Wi-Fi coverage or interference, not the FTTP service.
This is one of the most common causes of “slow fibre” reports.
2. Connect Directly to the ONT (Bypass the Router)
If speeds are poor even when wired into the router, the next step is to bypass the router entirely.
The Optical Network Terminal (ONT) is the small Openreach box installed where the fibre enters the building. Connecting directly to it helps determine whether the problem lies with:
- The router/firewall
- Or the FTTP connection itself
You can do this by setting up a direct PPPoE connection on a Windows computer.
This guide walks you through the process step-by-step:
https://www.digitalcitizen.life/how-setup-and-use-pppoe-internet-connections-windows-10/
If performance improves when connected directly to the ONT, the router is likely the issue.
3. Reset the ONT (Only if you’re comfortable doing so)
In some cases, the ONT itself may need a reset to clear minor faults or re-establish the fibre connection.
Before doing this, make sure:
- No one is actively using the connection
- You are comfortable accessing the ONT safely
Zen Internet provides a clear guide covering ONT diagnostics and resets here:
https://www.zen.co.uk/help-support/ont-diagnostics
⚠️ Important:
Do not repeatedly power-cycle the ONT, and never disconnect it during firmware updates.
What to Tell Us If You Still Need Help
If the issue persists after following the steps above, please contact our support team on 01302 260195 or via support@katcommunications.co.uk with:
- Wired and Wi-Fi speed test results
- Whether you tested directly from the ONT
- Any warning lights or error messages either on the ONT, router or on your browser
This allows us to diagnose the fault much faster and escalate it correctly if needed.
