error message

--- Please select a CRAN mirror for use in this session ---
Error in structure(.External(.C_dotTclObjv, objv), class = "tclObj") :
  [tcl] grab failed: window not viewable.

solution

> library(tcltk)
> tclServiceMode(TRUE)
[1] FALSE
> chooseCRANmirror(graphics = F)
53: Korea (Gyeongsan-si) [https]
54: Korea (Seoul 1) [https]
55: Korea (Ulsan) [https]