Help with Hypervolume package and changing colors

Hi All! I am having trouble using multiple colors on the hypervolume package, for some reason, it will only use the fist color given for everything. Any suggestions would be great. My code is below:

hv.sites = hypervolume(, method = "gaussian")
plot(hv.sites, show.contour = TRUE,contour.type = "alphahull",
contour.alphahull.alpha = 3, contour.raster.resolution = 4,
show.centroid = TRUE, colors = c("green", "red"))

Thank you!