[SECURITY VULNERABILITY] - Connecting to online services UNKNOWN ERROR

I've been aggressively trying to tackle this issue for the past few days spending close to 10-hours in various streams of EA tech support channels, and I think I'm getting close to finding the cause. 

Current theory is that after logging into Battlefield 6 on launch day (which would have used my account credentials to generate an authentication token), I changed my account details.
Which was all fine while my authentication token was valid.

Once that token expired however (potentially 24 hours later), Battlefield 6 was no longer able to create a valid authentication token which is leading to the error you're seeing. 

You might ask "But why is it not using my current account credentials to generate the auth-token?"

I dug deeper, and found that multiple iterations of my EA ID were able to log into my account using my current password.
I suspect this is a back-end bug that could be causing all kinds of authentication troubles internally.

Unfortunately, EA doesn't seem to want to take this legitimate cyber-security risk seriously... So here we are. Public forums. 

Check out the forum post below:
https://forums.ea.com/discussions/ea-app-technical-issues-en/security-vulnerability---multiple-ea-ids/12763070