How to navigate to this feature using the Menu
Click Help menu then Daedalus Diagnostics
How to navigate to this feature using the User Interface
If the Start Screen is visible, clicking on any of the icons at the bottom will take you to the Daedalus Diagnostics screen.
Click the Restart Cardano Node button to restart the Cardano node which is running in the background.
After a few seconds, the node will start.
This feature is useful if you are having trouble with your network connection. Sometimes using this can resolve network issues. Restarting the node is not necessary if Daedalus is functioning properly. Restarting the node at any time will not cause any problems.
See also 'Cannot Connect to Network' message
This feature was added in Cardano 1.3.0: Daedalus 0.11.0 and Cardano SL 1.3.0 - Release Notes