what is trace in hfss?

hello, i want to know that what is trace in hfss.
when i try to simulate my design with discrete sweep type then i get this error
"check the trace'dB S(1,1), it may have been edited"

Not sure about your application context - but in general "trace" is a PCB conductor.

It is referring a post processing plot of the Return Loss. When you changed the discrete sweep, you changed the x axis sampling and HFSS is informing you of this change... Also, this is not an error, but rather a warning and does not affect your simulation in any way.

Have Fun