What does CarSenseLost errors mean

While troublehshooting my sm(430). I am seeing CarSenseLost errors. What can this indicate the problem is?

1 of 2 things in most cases

miss match of link speed/duplex
or eletrical noise in the line.

move the ethernet cable away from high voltage and try to set the link speed and duplex on both devices to 10/h if you giving the customer more than 5 meg you’ll have to fix the line noise problem