Symptom: You are attempting to synchronize an Offline database with the Online (main/master) database, but get an error that the Online / Offline sync did not complete successfully. You are connecting to the Online database through the internet (including VPN).

What causes the sync to fail is an interruption in the connection to the database at some point during the sync. Given that the sync is attempted through an internet connection, this can be caused by various factors such as slow connection, intermittent connection from the ISP, traffic load on the ISP's network (sometimes depending on the time of day), network setup or configuration, just to name a few. These factors are out of the control of the application, and the exact cause of the interruption can be extremely difficult to diagnose.

In cases where a sync through the internet fails, the recommendation is to attempt to sync again. Syncs may not always be successful; sometimes it can take a few attempts (or more) before it completes successfully, some other times it will complete on the first attempt. Due to the Internet being a network of networks, there is no 'Quality of Service' guaranteed across networks and as such interruptions in connections can occur.