NFS Unbound - error code "FTCL50001"

So, I have the same problem, but I think I might found the problem (kinda), at least for me. So, after trying all the troubleshooting posted here, chat with some EA people and checked another forums and websites, nothing worked. So, I went like, OK I can't play online because every single time I try to enter the garage I'm kicked back to the main menu and offline, I'm screwed. Initially I thought the problem was related to making any kind of bank, I was wrong, wasn't that. After trying different approaches and things, I think I might found the problem: Is really simple, having too many cars in both story and online. I just sold a few vehicles, and the error went away. So far so good, no more error message, I entered the online garage multiple times with no issues, and also restarted the game a couple of times, no issues either. Disclaimer: it worked for me, I can't guarantee that will work for any one else. The problem, again: SO FAR, went away after I went below 50 cars in story mode (currently 45) and 130 in online mode (currently128). I have no idea if both numbers adds up, or is a separate thing, but those numbers worked  for me. Try it at your own risk. I just wanted to share what worked for me. I'm on Xbox series X. Cheers.