Go to File > Preferences and select System on the left. Hold the Control (Ctrl) key and click Expert in the upper right. A debug window named terminal appears alongside the main OnCall window.
Go through the steps that give you a socket/connection error and close OnCall. The app puts the debug log onto the clipboard upon closing. Email email@example.com us and paste whatever is on the clipboard in the message.
Turn off Debug mode and remove the terminal window by repeating steps in paragraph 1.