Xbox 360 emulator on xbox series X unable to connect to xbox live

I am having the same issue and same error code (80151912) when I'm running the Xbox 360 emulator on my Xbox series X.

I can sign into Xbox live on my Xbox series x but not on the emulator running the Xbox 360.

Same thing for me since tuesday on my Xbox 360. I also tried from my xbox series x, same result, unable to connect to live.

The games are all digitally owned in my library. There are no discs. I had no troubles with this on my original Xbox One that recently broke and required me to buy a new Xbox One S. The emulator I am referring to is the internal emulator that all Xbox
Ones run when playing a 360 Backwards Compatible game. When I install a 360 game and try to run it on my Xbox One S, the game will load HOWEVER I cannot connect to Xbox Live while in the 360 emulator. Due to a recent troubleshooting that suggests uninstalling
the game and clearing 360 cache and profiles, I would need to redownload my xbox live profile for the 360 emulator ON the One S. Since the emulator WON'T connect to Xbox Live, despite my Xbox One S BEING connected to Xbox Live, I cannot download my profile
and therefore cannot play and save my progress. I've tried with multiple games but they all give me the same issue of being "unable to connect to xbox live". I've tried all of the Mass Effect games, the Dragon Age games, Star Wars: The Force Unleashed games,
Banjo-Kazooie, and Fable series of games and NONE of these will allow me to connect to xbox live.

Xbox 360 games do not appear to see these users and I'm unable to select them when adding players to 360-games.

User accounts work differently on the 360 (and the 360 emulator on the Xbox One and Series X/S) to the way they do on Xbox One and Series X/S. The 360 had user profiles that needed to be downloaded first.

It's been a while so you'll need to bear with me. If remember you will need to sign in first with this other user you've created, then launch the 360 game. This will download the additional new profile to the console. I think, after this you should be able
to add this player to your game.

which is why the new Xbox series X is supposed to be able to play almost every game from every generation of Xbox console (including the original).

That's marketing spiel that's been misinterpreted. From how I understand it, the Xbox Series X will run most if not all Xbox One games. Which means at best, 100% BC with the Xbox One. It will also play all the games that currently on the Xbox One BC list
on the Xbox One.

Nowhere have said it will play almost, or all Xbox games from all the Xbox generations.

The problem with making all old games work is a hardware one. The Xbox 360 used a PowerPC 32-bit processor. The Xbox One and Series X use AMD X64 based processors. The Xbox One and the Series X are like PCs and they share the same processor architecture.

BC is achieved on the Xbox One because the BC team (with zero help from the developer) take the old 360 game and reverse engineer it to run on the Xbox One, taking the original 32-bit PPC executable archive and turning it into a 64-bit X64 executable. There's
no software emulation for the game. The only thing emulated in software is the 360 OS.

To run most games, or indeed, every game would require a software emulator for 360 games. A pure software emulator is a lot of hard work, far to complex to explain here.