Try without request.security

Something like this:

var float dailyOpen = na
var line  openLine  = na
var int   x1Line    = na

period  = dayofmonth
if period != period[1]
    dailyOpen := open
    x1Line    := bar_index
    openLine  := line.new(x1Line , dailyOpen, bar_index, dailyOpen, color = color.gray)
else
    line.set_xy1(openLine, x1Line,    dailyOpen)
    line.set_xy2(openLine, bar_index, dailyOpen)