Next to the Layers and Update menus is an area that both displays timeline error messages (in red) and a log of all messages sent by this instance of DeltaGUI as client to any DeltaServer. Find the small arrow on the right to open the log:
All messages are listed, with their source:
To track just one server connection, add the required IP Address to the filter, and only messages to this server will be logged. The log can be useful for identifying connection issues with any server.
Press Clear to delete all entries in the log. This page is also cleared when DeltaGUI is closed.