Unable to download my profile on xbox 360 (Error code : 8015190A)

I attempted to sign in to my Xbox live account and got error code 8015190A, after reading online at Microsoft how to fix the error code which was delete profile and download the profile again I get the same error code and unable to download my profile again.
I worked online with customer support who had me clear the cache 3 times and I still get the same error code. I am at a loss on how to proceed with fixing this code so that I can use my Xbox 360.

I've disabled F2A, tried everything I've read in the forums, and still can't re-download my profile on my XBOX 360. it starts go download bug then shows this error code. 8015190A

im trying to download my profile but i get error code 8015190A and this error code isnt able to be looked up

Yes I was able to download my profile on the xbox 360 before. It was my brothers x360 and I downloaded my profile on it previously before my brother gave it to me. All I did was delete his profile from the console and t hats when I started having the problem signining into xbox live so I then deleted my profile to download it again and it keeps on failing. I would download my brothers profile on it again and try but sadly he is no longer with us and I don't know his password. Its only on the x360 that im unable to sign in and download my profile. There was an error code that comes up but i cant remember it but i will list it when i next try downloading my profile again. The only error code I get is 8015190A but I don't get the error code all the time just sometimes other then that it just says that your profile failed to download try again later. How do you do a system rollback. That's the first iv e heard of that.

I tried a system rollback and when I tried to download my profile again it still fails and I get the error code 8015190A again.

1. This is an Xbox Series X console. The error happens when playing backwards compatible games. I had the same a similar problem in January of this year.

2. The console is not second hand. I'm the only user.

3. Yes, of course.

Under network settings, it says everything is fine. It's connected to the internet. It's connected to Xbox Live. NAT is open. When I play XSX or One games, there's no issue.

The problem is when connecting to Xbox Live through the 360 emulator. I got the error 8015190a. Support told me to delete the profile and clear the cache. Following that, whenever I boot a 360 game, it says "getting your Xbox 360 info". The loading bar does not move. After a couple of minutes, the screen fades to black and the game starts. Opening the guide shows that there's no profile. If I try to download a profile, it says "cannot connect to Xbox Live". There is no error code.

Some extra details:

In January I had the error 801540A9. This time the error was 8015190a. In both instances I was advised to clear the cache. In both instances, I was unable to redownload the profile (with some slight differences).

With the error 801540A9, I could at least access the sign in menu. I could enter my email and password, but the profile would fail to download.

With the error 8015190a, I am unable to enter my email and password.