Error in match.arg(position) : 'arg' must be NULL or a character vector

I have my first and very simple Shiny app and am getting this error: " 'arg' must be NULL or a character vector" My UI code is below. Any suggestions?

THANK YOU!

library("shiny")
library("plotly")

page_one <- tabPanel(
  "Page One",
  sidebarLayout(
    sidebarPanel(
      h2("Please enter Information"),
      
      radioButtons(
        inputId = "Color",
        label = "Select Color",
        choices = list ("black" = 1, "white" = 2)
      ),
      
      textInput(
        inputId = "graph_title",
        label = "Name of Graph",
        placeholder = "enter your text here"
      )
    ),
      mainPanel(
      h1("diversity Page"),
      p(
        "GRAPH WILL GO HERE"),
      ),
      
      textOutput(
        outputId = "message"
      ),
  
      )
    )

ui <-  navbarPage(
  "Midwest Demographics",
  page_one
)

sidebarLayout can take a sidebarPanel and a mainPanel, but you pass an additional textOutput(
outputId = "message"
) which can't go there... So perhaps put it inside either the sidebarPanel or the mainPanel, or come up with a different layout altogether.