After one of these smaller regular updates of COD MW (about 185 MB) I got the SIGN IN-error BLZBNTBGS000003F3 that tells you that there is/was a server disconnecion from the game servers. I tried most of the suggested solutions from different forums (Blizzard, Activision, Warzone, as well as some suggestions to clear the game cache folders, logging in with different global locations, reinstalling Blizzard launcher etc.) nothing solved the issue (I did NOT reinstall/download the whole game though!).
Turned out for me that the problem occured due to the firewall I used (ZoneAlarm free edition). Tricky thing was that this firewall has a feature that allows you to stopp it running for a small period of time so that you can check if a connectivity problem you have may be due to the firewall running. But the COD connection error persisted even when the firewall was “paused”. Then I decided to try a more radical approach and uninstalled ZoneAlarm instead of only pausing it. After that I could start COD again without any problems. Even after reinstalling ZoneAlarm and running it COD has no connection problems anymore.
I know this is a pretty specific solution/problem but it indicates that
- there is a good chance that the cause of this BLZBNTBGS000003F3 error might be found rather on the user side (e.g. due to firewall settings, antivirus settings, security settings) than on the game server side
- you don’t need to download/reinstall the whole huge game again and rather spend your time falsifiying if a/which security app might cause the problem.
Maybe this helps someone good luck and see you in the WZ 