Persistent Unknown Error 0:51002S:57019S – Authentication Failure?

Hey everyone,

I’m currently locked out of Battlefield 6 with a recurring "UNKNOWN ERROR" message on startup. I am playing the PC version through Xbox Game Pass Ultimate.

Error Code: 0:51002S:57019S

1. I have already run through the standard troubleshooting checklist, but the issue persists. Here is what I have tried so far:
2.  Restarted my PC and the game
3. Completely reinstalled Battlefield 6
4.  Reinstalled the EA App
5. Reinstalled EA AntiCheat
6. Set a proper Google DNS and flushed the DNS resolver cache

Based on some research, this specific string often points to a failure at the handshake/authentication phase. A few older threads suggest this can be caused by the modem generating a private IP address instead of a public one, which might require changing the modem's WAN settings from NAT to Bridge mode. I also saw some players mentioning that the connection only works when using Cloudflare WARP.

Before I start reconfiguring my modem hardware or routing my traffic through external tools, has anyone else encountered this error recently on PC/Game Pass and found an alternative fix?

Any suggestions would be massively appreciated. Thanks!

Have you noticed if this error happens at specific times of the day, or is it a permanent lockout every time you try to launch?