Syncthing does not run automatically after Linux starts. Use this method to enable the user level service for desktop environments. This ensures Syncthing starts whenever you log into your session.

First enable the service for your current user by running this command in the terminal: 

systemctl --user enable syncthing.service

The terminal should return a message confirming the creation of a symlink from your configuration folder to the systemd service file. This confirms that Syncthing is scheduled to start at login. 

The service will officially start the next time you log in. Restart your computer and verify that Syncthing is active by running: 

systemctl --user status syncthing.service