HELP! Xbox 360 update failed/Xbox Live connection issues

First time Xbox user here. I recently purchased a used Xbox 360 slim from Facebook Marketplace. I’ve never played Xbox before but I’m usually pretty tech savvy so I thought I could figure it out but I am having trouble connecting it to my network/getting it to update.

Background info:

I have a fiber ISP called Hotwire Fision and I use their rental router called Eero. The UPnP in my router settings is on so I know that’s not the problem.

Issue 1:

When I click Test Xbox Live Connection, a screen pops up saying “test failed. There’s a problem with your connection. Let’s try to fix it. (Null)”. When I click Show Suggestions it says IP Address Error at the top then shows the first suggestion to unplug router and reconnect (which doesn’t fix the issue). Then it says “can’t obtain an IP address from your router or modem.” It the gives me a website for www.xbox.com/ipaddress-help (which page doesn’t exist). So I go through the other suggestions. One says to try a static IP address. I don’t know how to do that on my own. Another suggestion talks about MAC filtering possibly being the issue but I don’t know anything about that either.

Issue 2:

So I click Configure Network, go over to Additional Settings, and click Restore to Factory Defaults. Then I try it again by clicking Test Xbox Live Connection again and this time it shows Network: Connected, Internet: Connected, then before it shows the result for Xbox Live a screen pops up saying Update Required. I click yes to update, it goes through the download, but then a screen pops up saying “Update Failed. Can’t process the update. If the problem persists, go to www.Xbox.com/support. Status code: 43C5-4497-1380-267F-C000-0185”.

Additional info:

I have formatted the hard drive and cleared system cache in the storage settings. Also, I tried to manually assign my IP Address, by typing in the IP Address, Subnet Mask, and Gateway address I found in my router settings but that doesn’t work either. I’ve tried wired and wireless connections and both give me the same issues. Another thing to note is when I insert a game disc in the console, the game works. I am just having trouble with Xbox Live not connecting/the update failing.

What am I doing wrong? Does anyone know how I can get the console to connect/update? Any guidance at all is very greatly appreciated!

Thanks!

-Julia

:)