Boto doesn't handle gov cloud S3 urls correctly
Open file like: sudo nano -iw /home/zulip/deployments/{date}/zulip-py3-venv/lib/python3.6/site-packages/boto/s3/connection.py
Edit Lines:
Line 140: DEFAULT = 'us-gov-west-1' # US Classic Region
Line 164: DefaultHost = 's3.us-gov-west-1.amazonaws.com'