The connection was dropped during the transmission. This is quite often identified with networking or system administration misconfigurations or downtime.
Causes
- Typical network connection issue
- Downtime of exchange server
Fixes
Step 1: Transient Error
This can be a transient error, but if the error continues further, then you need to analyse your network devices like router, network card.
Step 2: Local Internet Connection
Check your computer local internet connection, after confirming no local network issue exist, audit conceivable server network related issue.