I've made a Heatmap using the ComplexHeatmap function in r and am trying to add a column annotation using the HeatmapAnnotation function, however i keep getting this error:

Error in as.character.default(col) : 
  no method for coercing this S4 class to a vector

here is what ive been doing. I know its a simple heatmap function in terms of the annotation.

Heatmap(matrix_t,
        cluster_columns=FALSE,
        row_names_side = "left",
        row_names_gp=gpar(cex=fontsize),
        clustering_distance_rows ="maximum",
        clustering_method_rows = "ward.D",
        km=2,
        HeatmapAnnotation(df = Gene_info, which = c("column")))

The Gene_info is already a data.frame.