R GGMAP HTTP 400错误请求

Question

我正在尝试遵循以下教程https://www.r-bloggers.com/mapping-seattle-crime/，但无法加载GGMAP。

我已经激活了Google API，并使用register_google（）注册。但是在调用GGMAP

后出现以下错误

map_city <- qmap(location = "seattle", zoom = 11, source="stamen", maptype="toner",darken = c(.3,"#BBBBBB"))

Error in aperm.default(map, c(2, 1, 3)) : 
  invalid first argument, must be an array
In addition: Warning message:
In get_googlemap(center = location, zoom = zoom, filename = filename) :
  HTTP 400 Bad Request ```

How can I resolve? Thanks.