I am trying to apply a notch filter to data with powerline frequency contamination at 60Hz harmonics. For some reason I cannot apply the filter to 120 or 180 Hz and they are instead attenuated. This worked a couple days ago with the same dataset. When trying to apply all 3 I get the error "notch filter frequency cannot be above 300 Hz". Why might this be occurring? I attempted to apply 120Hz alone and it also won't work.