AT&T Broadband Blinking Red: What It Means and 5 Ways to Fix It

Internet outages are never fun. One minute you’re happily working away at your computer, and the next you’re having to troubleshoot router issues.

One of the most common issues you might experience with AT&T’s internet service is that on the front of the router, it starts blinking red light, and suddenly you won’t be able to access the internet.

It’s a frustrating thing to deal with, but don’t worry! We will walk you through both reasons causing the red and the best ways to go about solving it so you can get back to work unimpeded by annoying router errors.

Why does your broadband light is blinking red? 

att broadband blinking red

We have scoured both AT&T’s support articles and user forums to concisely put together all the issues that cause this. You can easily follow this guide through to rectify the problem yourself.

The red blinking light broadly means there is an issue with the internet, and it’s not able to establish a connection to it. Of course, this is only half of the information that we need, as it doesn’t tell us exactly what is causing the internet connection problem.

Here are a few of the primary reasons why you may experience your AT&T broadband red light flashing.

ISP service interruption

Internet service providers such as AT&T will often experience service outages in particular areas. This could be due to an external hardware issue at their end, power outages, or they will sometimes need to perform service/maintenance and need to temporarily disable the service to a particular area so they can complete their work.

Unfortunately, there’s nothing on your side to do here. You just have to wait for them to complete their work and for the service to be restored.

To see if this is the cause of your issue, you can check on the AT&T service outages webpage to see if your area is currently affected. If you are unable to access this website, you can also call AT&T support to inquire about this.

Invalid login credentials

Another common issue that can prevent the gateway from authenticating is invalid login credentials or an IP address conflict.

This will require you to log into the AT&T router via a browser (or sometimes internet service providers will also have an app you can download) and double-check all of the entered information and login credentials to make sure they are correct.

Faulty firmware/software updates

Sometimes the AT&T modem hardware itself, or its associated software/apps, needs to be updated (this can sometimes be automatic, too).

Unfortunately, these updates are not always bug-free and can cause problems with a system that was previously functioning just fine.

This can usually be rectified by resetting the AT&T router or reinstalling any associated software.

Power/ broadband cable issues

If an Ethernet cable is not correctly seated, or a power cord has been damaged, this can stop the AT&T modem from functioning normally and prevent it from establishing a connection to the internet.

Sometimes otherwise working cables can suddenly fail, in which case swapping them out with working ones may solve the issue.

Defective hardware

If a particular component within the router hardware itself fails, or if the unit has become damaged in some way (due to a drop or other such accident), this can also prevent the unit from being able to establish a solid internet connection.

This is a little more difficult to solve and will usually require AT&T service to be contacted for a replacement.

How to fix AT&T broadband light blinking red? 

As you can see, there are a number of potential causes for this flashing red light, and we will need to go through and troubleshoot these one by one in order to quick fix your router.

We will walk you through all the steps you need to take in order to troubleshoot these quite common issues. Follow them in order so you can be sure you’ve covered as many bases as possible.

Contacting AT&T support for a replacement device is really the last resort, and there is a high chance the suggestions listed here will solve your issue. 

Hard-reset the router

A simple soft resetting your router is a very simple and often reliable way of fixing any bugs or errors that the device has gotten stuck on.

Unlike a soft reset where you will simply press the reset button and let it restart, a hard reset involves completely unplugging the device from the power and letting the device sit for a minute to let all residual energy within the device dissipate.

This is also known as “power cycling” a device.

After the unit has been disconnected from the power for about a minute, plug the power cord back in and allow it time to boot up. This might take a bit longer than usual.

After it’s booted up, it will attempt to reconnect to the internet as normal, and if successful, let see if the light will return to a solid bright white light, non-blinking color. 

Update any associated firmware or software

Over time it’s possible that your software or hardware’s firmware will become out of date. We recommend keeping this up to date for security reasons, and oftentimes updated software will address various bugs and issues that might have been causing problems with connecting to the internet.

Updating the software is a simple process. If it’s an app, you can simply find it in the associated app store for both Android and iOS. Locate the app, and if there is an update available, it will have a button underneath the title of the app that you can simply press to update.

If it’s computer-based software, you can go to the AT&T dedicated software update website to check if there is any available update to the software.

That’s it for software. However, updating the firmware on a piece of hardware is a little more involved. Here’s a step-by-step guide on how to do this:

  1. Ensure your device is connected to your computer via an Ethernet cord.
  2. Type in your IP address into a web browser.
  3. Enter your login details to gain access to the device.
  4. Select the “software update” button, and your device will check if there is an update available.
  5. If one is available, it will give you an install prompt. Simply click that, and it will update the firmware on your device.

Do not unplug or restart the device while this firmware is updating or it may cause the device to become non-functional.

Check power/Ethernet cables

A non-functioning cable or faulty power cable can easily prevent a router from connecting to the internet.

Double-check that all cables are correctly seated. For Ethernet cables, you should hear a definitive click when it is correctly plugged in. The small tab that holds it in place is quite susceptible to breaking off, which will prevent the cable from keeping a steady connection to the device.

If this has happened, you can replace that cable in order to ensure that is not the issue.

Factory reset

This is a slightly more extreme approach to power cycling the device and will remove all firmware updates and user settings to restore the device to how it was originally shipped from the factory.

This can work well if an update has failed or to solve more severe issues that the previous steps did not address.

To do this, take a small, thin item such as a paperclip and press in the small button which is hidden inside a tiny hole on the back of the device. This will usually have the word “reset’” printed above it.

Keep this button held in until all the lights on the device turn off. Then, remove the paperclip and give it time to reset. It will then boot up by itself.

After this is done, you can re-apply any firmware updates and see if this fixes the issue.

Contact AT&T customer support

Once you are sure the software is updated, the cables are working, and have tried a hard reset of the device, it may indicate that there is an internal component failure and that the device is faulty.

If this is the case, then the next step is to contact AT&T service in your area. They will assist you with troubleshooting, and after ascertaining that the issue is due to faulty hardware, they will normally send you a replacement if it’s not something they are able to diagnose over the phone.


Here are some common questions people have when their at&t router blinking red. 

What does it mean if there is both green light and red light on the Broadband?

Sometimes your notification may not just be blinking red. In certain circumstances it will flash between both red and green.

Unlike a purely red blinking light, a green light which then blinks red means it was able to establish a connection, but the connection is either very weak or wasn’t fully able to authenticate. 

If you happen to have this issue, all the troubleshooting tips we mentioned above still apply, particularly when it comes to the device position to increase the signal strength.

What if I only have a red flash light on broadband 2?

Some AT&T modems will have Broadband 1 and Broadband 2.  This means that additional internet infrastructure in your house is being utilized to achieve faster speeds.

In some scenarios, Broadband 1 may be functional, but Broadband 2 will see a red light on your at&t.  

You should find that the internet is still working in this case, as Broadband 1 does most of the heavy lifting. However, you will still want to go through the troubleshooting tips mentioned in this article as fixing Broadband 2 will increase your download/upload speeds significantly.

5/5 - (5 votes) Protection Status