为什么在R中使用“展示位置”包时得到“ OVER_QUERY_LIMIT”

Question

## install the package "placement" 
## install.packages("placement")
library(placement)
##============= First Run:
## Without using Google API Key
##  Get coordinates for the Empire State Building and Google
address <- c("350 5th Ave, New York, NY 10118, USA", 
             "1600 Amphitheatre Pkwy, Mountain View, CA 94043, USA")
 coordset <- geocode_url(address, auth ="standard_api",  privkey= "",
                         clean=TRUE, add_date='today', verbose=TRUE)
## View the returns
print(coordset[ , 1:5])
##============= Output:
## lat lng location_type formatted_address           status
## 1  NA  NA          <NA>              <NA> OVER_QUERY_LIMIT
## 2  NA  NA          <NA>              <NA> OVER_QUERY_LIMIT

我只使用了一组lat-long，所以我不确定为什么要加入OVER_QUERY_LIMIT。期待对此的解决。提前致谢。