Diablo 4 error code 401003: How to fix, possible reasons, and more

The early access phase for Diablo 4 has just begun. While the title launches globally on June 6, 2023, franchise fans who have pre-ordered the Digital Deluxe or the Ultimate Edition will be able to log in to the game and go on a demon-killing rampage. However, given that it's just gone live, there's a high chance many players around the globe will end up seeing error codes.

Now, error codes are a good way to designate, identify, and finally solve the issue at hand. The error code 401003 is one of the many codes that players have been facing with Diablo 4. But why does this occur, and what are the potential workarounds for it?

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Reasons for Diablo 4 error code 401003 and potential fixes

The Diablo 4 error code 401003 appears whenever there your game automatically disconnects from the network and tries to reestablish the connection once again. This is more of a client-side issue, so any troubleshooting will have to be done on your end.

The very first thing that you should do is restart Diablo 4. In most cases, restarting a game usually forces it to establish a new connection with the server. There's a high chance that the error code won't appear once the game has been restarted.

In case the above method does not solve the issue, you need to start troubleshooting your network devices. Check if your device is connected to the internet. If it's not, you need to reconnect it.

If that doesn't solve the problem, restart your modem and your router. Since it's a disconnection issue, a simple restart could often solve your problems. While you're restarting your network devices, it's wise to restart your desktop or your laptop as well.

If none of these work, your device's firewall might be blocking Diablo 4 from connecting to the network. In this case, all you need to do is allow the app through the firewall on your Windows device.

Head to the start menu and type "allow an app through firewall." Click on the very first option that you get, and then hit the "Change Settings" button. To allow the game through the firewall, just click on the checkbox beside it.

If these aforementioned methods don't work out for you, you need to get in touch with your ISP and see if there is an issue with the wiring. The error code 401003 pops up only when there's a client-side issue, so there's nothing much that the developers can do about it.

Diablo 4 has managed to impress players through the beta stages and is doing so even during the early access period. It will be interesting to see how the players react to it in the coming days.