The 'map.where' function does not provide country names from geographic coordinates

Question

My dataset assembles some geographic coordinates, as can be seen below:

dput(head(data))

structure(list(Latitude = c(-25.600992, -22.996431, -22.954634, 
-12.983684, -22.990209, -22.955409), Longitude = c(-48.38602, 
-43.25945, -43.062178, -38.520737, -43.191247, -43.174349)), row.names = c(NA, 
6L), class = "data.frame")

I imported the above data into R, and I ran the following commands, in order to identify the country names based on latitudes and longitudes:

setwd(choose.dir())

data <- read.table("Coordinates.txt", h = T, sep = "\t")

library(maps)

data$Country <- map.where(database = "world", data$Longitude, data$Latitude)

However, in the new dataset, the Country column, instead of showing the country names, showed only NAs:

dput(head(data))

structure(list(Latitude = c(-25.600992, -22.996431, -22.954634, 
-12.983684, -22.990209, -22.955409), Longitude = c(-48.38602, 
-43.25945, -43.062178, -38.520737, -43.191247, -43.174349), Country = c(NA_character_, 
NA_character_, NA_character_, NA_character_, NA_character_, NA_character_
)), row.names = c(NA, 6L), class = "data.frame")

How could I solve this problem in order to get the country names from the coordinates I have?