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Common problemT-FiberHome internet
T-Fiber internet not working
Loose cable, fiber line fault or router issue
T-Mobile Fiber says a dead connection usually comes from a loose or damaged cable, a fault on the fiber line (shown by the PON light), or the router. A VPN or firewall on your device can also block access.
How to fix it
Check that the router's power cable and other cables are firmly connected.
Look at the lights: Power, PON, Internet and WLAN should be solid green or cyan.
If the PON light is off or flashing red, contact T-Fiber support by chat because the fault is on the fiber line.
If you have a separate ONT box, unplug it for 10 seconds, plug it back in, wait 2 to 5 minutes, then restart the router.
Turn off any VPN or firewall on your device and try again.
Check the router status under My Network in the T-Mobile Fiber app.
From T-Fiber's help pages: fiber.t-mobile.com, in our words. Checked on 5 November 2026. If the steps do not help, T-Fiber's own support is the next stop.