It means the instrument is not properly geting the reagents of its need like sheath solution, shutdown etc. Generally after repeatedly on off this error is solved but if not solved u have the only option to call instrument service engineer. Thanks

Have you tried doing bubble purge and degas?

This is the standard error message when the machine is out of buffers - typically the shut down buffer (i.e. dH20). Just fill up that container and you should be all set

Thank you for all your answers. The problem has been solved. Erroe 'e040' of FACS CantoII means that the tube sensor cannot detect if the tube is present or gives a wrong signal that the tube is already there. It usually occurs if there is salt (usually from splatters of PBS or other buffers) or some dirt accumulated on the tube sensor. After cleaning the tube sensor it started working again.