Why does the chart_Series chart look blurry in Shiny?

[mytarmail]

Hi! Why does the chart look blurry in shiny and how can I fix it?

ui <- fluidPage( plotOutput("Chart") )

server <- function(input, output) { output$Chart <- renderPlot({ chart_Series(symb) }) }

shinyApp(ui, server)

The question was asked in more detail here.