AT&T Internet Not Working — Gateway & Fiber Fixes

Applies to: AT&T Fiber and Internet Air, BGW320 and similar gateway models

JRWritten by Jordan Reyes, Networking & Connectivity Writer · Last reviewed Sep 2026

Quick answer: A flashing red Broadband light means the gateway can't reach AT&T's network at all — check for an outage first, then do a full power cycle and inspect the fiber connection before assuming the gateway itself is faulty.

1. Read the Broadband light

Solid white/blue: connected normally.
Flashing white: starting up or updating — give it a few minutes before assuming anything's wrong.
Flashing red: the gateway can't connect to AT&T's network. This is the most common "no internet" signal and the one this guide focuses on.

2. Check for an outage before anything else

Use the myAT&T app or website from a phone on cellular data to check for a known outage in your area. If one's listed, there's nothing to troubleshoot locally — it resolves on AT&T's end.

3. Do a full, clean power cycle

Unplug the gateway's power — remove the battery too if it has one.
Wait a full 20-30 seconds, not just a few.
Plug it back in and give it several minutes to fully reconnect before checking again.

4. Check the physical fiber connection

If you're on AT&T Fiber, the connection between your gateway and the ONT (the small box where fiber enters your home) matters more than people expect.

Make sure the fiber patch cable isn't bent sharply or kinked — fiber is sensitive to tight bends in a way copper cable isn't.
Gently reseat the connection at both ends if you're comfortable doing so; avoid forcing anything.
Don't unplug the gateway while it's mid-update (a white/amber blinking pattern usually indicates this) — interrupting it can cause further issues.

5. Using your own router instead of AT&T's gateway?

If you've set the AT&T gateway to Passthrough Mode so a separate router gets the public IP directly, and you're seeing "connected, no internet" specifically on the router side after an outage or reboot:

Confirm Passthrough Mode is still set correctly in the gateway's settings — this can occasionally reset after a firmware update.
Power cycle the AT&T gateway first, then your own router, in that order — not simultaneously.
Confirm your router's WAN connection is set to DHCP/Automatic so it can actually receive the public IP the gateway is passing through.

6. Devices show connected to WiFi, but no internet

If your phone or computer shows connected with full signal but nothing loads, try flushing DNS on the device itself before assuming the gateway is the problem: on Windows, open Command Prompt and run ipconfig /release, then ipconfig /renew, then ipconfig /flushdns. On a phone, toggling WiFi off and back on often achieves the same result.

Be cautious searching for "AT&T internet support phone number" — a number of sites and even some hijacked forum/review posts circulate fake support numbers designed to catch frustrated customers. Contact AT&T only through the official myAT&T app or att.com.