Why am I getting "Error Code" after starting the COD-MW3 game..??? ( DEV ERROR 5479 )

I have the same error. Did you contact activision support?

Master ET I have done all steps of your trouble shooting advice. It is not my internet, modem, or router connection. I'm hard wired and all connection tests are good. I've even uninstalled and reinstalled COD MW3. Why am I still getting an sys error content no longer available on my Xbox Series X. However on my Xbox Series S this game is working just fine. I also did a side by side comparison of game updates and I have the latest version. Please what do you advise for me to do or who should I contact? This is just extremely frustrating and disappointing when I've spent soo much money for the Xbox Series X Console and Vault Edition for COD MW3. I just want to unwind from a long day of work and in the comforts of my home to a good game of zombies. I'm beyond frustrated and disappointed. Please anyone help or point me in the right direction to get help with this problem. Thanks.

Just wanted to give the Xbox community an update. Master ET solution worked after 3 repeated attempts. I did all of Master ET steps 3 consecutive times and for some reason it worked after my 3rd entire reset, including reinstalling MW3. It's still ridiculous that we have to do all of this just to play. Thank you.

Turn-off your Xbox, Disconnect your Xbox, Router, and Modem power source for about 1-minute (All devices should be disconnected/unplugged from their power sources).

Then reconnect/plug-in the Router and Modem power source. Wait 2-minutes, until all the lights are on and steady.

Reconnect/plug-in your Xbox power source, turn-on Xbox, wait 2-3 minutes after the Start-up System is finished.

Go to: SETTINGS, GENERAL/ Network Settings, Test your “Internet Connection”…All Good..!!

Now, “Test NAT type” (twice) …All Good..!!

START: Your Game, wait 1-minute for any updates. After the game restarts from updates, Power-off/Restart your Xbox Console.

“…PLAY THE GAME…”

((…In Addition…))

If the game is already purchased…Go to:

Xbox Menu, “My games & apps”, See All/ “Games”, {toggle over to your selected game} - [“MANAGE GAME”]

[“Call of Duty”]

[238.4 GB] - Version- 1.0.34.0

0-Updates… Check and start your “Queue”…or… Reinstall the game from the “Purchased-Menu”

…All Good..!!

Ok. How do you fix this error if digital assistant was never set up?

I have the same issue. Paid $100 for vault edition and nothing but errors all the time and friending is locked. Can’t send requests, can’t get requests. It’s a total rip off and I want my money back.