error Error in eval: object 'adver_TV' not found

Hello,
I get always this error when i want to evaluate a linear model.
my steps
1 downloaded dataset on kaggle
2 created my model and saved it as .rds file
3 saved this file in folder of my shiny app
4 wrote this code for my shiny app

library(shiny)
library(nnet)
library(caret)
#create dataframe newdata for storing predictors, choosen by the slider input
newdata<-data.frame(c("adver_TV"))

ui <- fluidPage(

  # App title ----
  titlePanel("Marketing"),
  sidebarLayout(
  # Sidebar panel for inputs ----
  sidebarPanel(

    # Input: Slider for the number of bins ----
    sliderInput(
      inputId = "bins",
      label = "total budget advertentions:",
      min = 1,
      max = 500,
      value = 30
    )
  ),
  mainPanel(
  # Output: result ----
  verbatimTextOutput("Sales")
)
)
)
# Define server logic required to draw a histogram ----
server <- function(input, output) {

    #model
    model<-readRDS('Simplemodel.RDS')
    newdata[1]<- reactive({input$bins})
    output$Sales <- renderText(predict(model,({newdata})))

}

# Create Shiny app ----
shinyApp(ui = ui, server = server)

What did i do wrong? can someone help me?
Kind regards and thx for your time,
Nobel

Hello,
I found it myself. Its a problem about reactivity.
Solution is place whole server-part between observe({ server code})