How to Fix AT&T gateway authentication failure

If you have started seeing the AT&T gateway authentication failure error message and can’t connect to the internet, you are at the right place. In this article we are going to guide you through the necessary steps in order to fix this issue.

What causes AT&T gateway authentication failure?

This problem generally occurs when you replace your equipment with a new one so some cables get loose, disconnected to plugged in the wrong place, after storms and power outages in your area

Fixing the AT&T Gateway Authentication Failure

Whatever the reason for the gateway authentication failure is, we did our best to cover all situations and ways to fix this problem.

So, let’s begin!

1. Check the cables and connections between the ONT and the AT&T gateway

When we are replacing our equipment or maybe cleaning around, in some cases the cables get disconnected or get loose.

So, the first thing to do here is to check all the connections and see if everything is firmly connected. While you are doing that check whether the Ethernet network cable is connected to the correct port on your ONT.

ONT port on AT&T gateway

For example, the Ethernet cable from the ONT or the data jack has to be connected to the ONT port of the gateway. It is usually labeled as ONT and its colored red or orange depending on the AT&T gateway.

Now try to set up the gateway and see if the problem is still there.

NOTE: When you are replacing your old equipment with a new one it is better to position the one next to the other and then remove the connection from the old one and plug it into the new one.

2. Reboot (Power cycle) your AT&T router

One of the simplest solutions that makes any electronic device up and running is rebooting. This simple reboot (restart or power cycle) solves the problem in almost all cases.

This can be done either manually or with the help of the Smart Home Manager if your AT&T gateway is compatible with it.

How to do it manually

  1. Take the power cord from the back of the AT&T gateway and unplug it. Remove the battery if there is one and also unplug the phone cord from the gateway if you use DSL.
  2. Wait at least 20 seconds.
  3. If you have removed the battery before place it back in.
  4. Take the power cord and plug it in again. If you have DSL connect the previously disconnected phone cord.
  5. Now leave the gateway for about 10 minutes to boot up again and the AT&T router lights on it to stabilize i.e. to turn green.
  6. After you restart the gateway try to connect to the Internet to see if the AT&T gateway authentication failure is still present.

3. Check if there is a service outage in your area

Sometimes a service outage in your area will give you the gateway authentication error message. You can easily check if there is one using the AT&T Service Outage Information page. If you have no internet at the moment, use your mobile internet to check.

Just sign in and you will see whether you are affected by a service outage. There is an option to be notified when the service outage gets resolved.

4. Use the MyATT app to resolve service problems

Download and install the myAT&T app (App Store or Google Play)

Launch the app and click on “Support” at the bottom of the screen. Now, select “Internet” and use the Fix It Now diagnostic tool. The tool will start the troubleshooting process and recommend further steps.

5. Factory reset the AT&T gateway

Resetting the gateway is one of the last solutions we recommend but you have to know that this will delete any customizations you have made in the gateway settings like a custom network name or wireless password and so on.

Check these official guides on how to factory reset your AT&T gateway.

NOTE: Please note that in some cases you will have to hold the Reset button for more than 30 seconds.

Final Thoughts

We hope that you have managed to fix the AT&T gateway authentication failure at one point while reading this article. In case nothing of the above helped it is recommended to contact the AT&T customer support. They will help you resolve the problem or even replace your gateway with a new one in case they figure out that the problem is caused by a defective gateway.

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