The TWS is configured to automatically log off each day at 11:45 PM local time for operational and performance purposes.
Clients can adjust the time at which it occurs each day by selecting Edit and then Global Configuration options from the TWS menu and then the Lock and Exit selection from the Configuration pane. There you may adjust the HH:MM and AM/PM election for the Auto Logoff Timer. Clients can also specify a time of day for the application to automatically restart (without authentication requirements) by selecting Auto restart. Please review auto-restart considerations before using this feature.
Clients using IB Gateway to connect a third-party application via API have the option of running it continuously for up to a week, from Sunday to Sunday, from a single user authentication. From menu Settings select Configure, then Lock and Exit and check Auto Restart. If this option is chosen, IB Gateway will attempt to restart daily during the week without any required intervention by the user. More information on IB Gateway can be found in the TWS API documentation.