This error occurs when there's an issue using third-party credentials to log into Blizzard services. This is likely due to a timeout or communication disruption between our servers and the third-party site.
Wait a few minutes and try logging in again. If the issue persists, try the following steps:
Reset your network devices to make sure your router hasn't become flooded with data.
Close all other applications to resolve software conflicts and free up resources.
Update or temporarily uninstall any security programs, which may mistakenly identify the login module as a security threat.
Check your network configuration to find any issues with your firewall, router, or port settings.