Error Code: BLZBNTBGS80000035 (9001)
This error occurs when the connection to Facebook authentication servers is lost and your information wasn't able to be sent or received. Before you contact us for assistance, try the following troubleshooting steps.
Reset your network devices to make sure your router hasn't become flooded with data.
Try closing background applications to resolve any software conflicts.
Restart the Battle.net desktop app to clear any stalled Agent processes.
Disable or temporarily uninstall any security programs, which may mistakenly identify the login module as a security threat.