Enabling diagnostic logs are often recommended when troubleshooting 4D specific network issues. If a server disconnect had just occurred, then the file of interest will be the last numbered diagnostic file. When viewing the last diagnostic file in the Logs folder, the first thing that can be tracked is the exact time of the crash which can be done using any text editor and searching for the text "critical net trigger" as shown below:



Note that each line is prefixed with a timestamp which can be extremely useful for narrowing down the time of the crash. The diagnostic log alone can't always pinpoint the exact reason for a disconnect, but using the time frame can be used in conjunction with other logs like debug and client-server requests logs to track down which commands were called around that time.