Xbox 360 will not sign into xbox live. Possible false console ban?

Ok, so it seems connecting my 360 to my phone as a hotspot allows it to connect to xbox live. Im at a loss for what to try next. I just put it in a dmz on my router and it still won't work when connected to it

Edit: it downloaded the update and now no longer works. Odd.

I have already done that, no luck unfortunately

I'm having the same problem; I have tried to suggested fixes and nothing seems to work.

It's been happening to me for several days, randomly on one of the days I could sign in and now I can't and get the same error as you.

Well its definitely not a console ban. That much i can say. It it were it would display a message saying specifically that this console is banned permanently.

That being said a few people on reddit said the following worked for them:

This came from https://www.reddit.com/r/xbox360/comments/2d40y5/connecting_to_xbox_live_error_code_8015190e/

Hope this helps:

You can sign in on different console models at the same time, but not on the same model. For example signing in on Xbox One and Xbox 360 is possible. But it is not possible to sign in on two Xbox 360 consoles at the same time or on two Xbox One consoles.