Apple released macOS 10.12 Sierra on 9/20/2016. Some customers are reporting Office 2016 for Mac applications are closing unexpectedly, or crashing when an Office application is launched, or when the computer is moved between Wi-Fi networks (e.g. moving a laptop from home to work).
Customers in a workplace or school network configuration who wish to upgrade to macOS Sierra should update to macOS Sierra 10.12.2 or later for improved stability specific to proxy networks.
WORKAROUND
Turning off “Auto Proxy Discovery” or “Automatic Proxy Configuration” is a possible workaround, if allowed by your organization’s network configuration.
Go to System Preferences and open Network.
Click on Advanced and go to Proxies.
Check if "Auto Proxy Discovery" or "Automatic Proxy Configuration" is turned on.