Error deploying Shiny app on shinyapps.io - Failed to determine "appPrimaryDoc"

Tried to Deploy Shiny app to shinyapps.io but encounter this message. What should I do?

── Preparing for deployment ────────────────────────────────────────────────────  
✔ Deploying "R-shiny-assessment" using "server: shinyapps.io / username: xxx"  
Error in `inferAppPrimaryDoc()`:  
! Failed to determine `appPrimaryDoc`.  
✖ No files matching "\\.html?$".  
Backtrace:  
    ▆  
 1. └─rsconnect::deployApp(...)  
 2.   └─rsconnect:::appMetadata(...)  
 3.     └─rsconnect:::inferAppPrimaryDoc(appPrimaryDoc = appPrimaryDoc, appFiles = appFiles, appMode = appMode)  
 4.       └─cli::cli_abort(...)  
 5.         └─rlang::abort(...)  
Execution halted  

My code:

library(shiny)  
library(readxl)  
library(openxlsx)  
library(dplyr)  
library(tidyverse)  
library(ggplot2)  
library(rsconnect)  


ui <- fluidPage(  
  
  titlePanel("Claim Data Upload"),  
  
  sidebarLayout(  
    sidebarPanel(  
      sliderInput("tail_factor",label = "Please adjust Tail Factor",  
                  min = 1,max = 2,value = 1.1,step = 0.1),  
      
      fileInput(inputId = "file",label = "Upload your file",accept = ".xlsx")  
    ),  
    mainPanel(  
      tableOutput("content"),  
      plotOutput("graph"),  
    )  
  )  
)  
server <- function(input,output,session){  
  
  excel <- reactive({  
    req(input$file)  
    data.frame(read_excel(input$file$datapath))  
  })  
  
  output$content <- renderTable({  
    req(input$file)  
    data.frame(read_excel("testing.xlsx","sheet3"))  
  })  
  
  #Graph Creation  
    
  data2 <- read_excel("testing.xlsx","sheet3",skip = 1)  
  data2 <- as.data.frame(lapply(data2,as.numeric))  
  
  data2_long <- data2 %>%  
    gather(variable, value, -Loss_Year)  
  
  output$graph <- renderPlot({   
    req(input$file)  
    ggplot(data2_long, aes(x = variable, y = value, color = factor(Loss_Year), label = value,   group = Loss_Year)) +  
      geom_point() +  
      geom_line() +  
      geom_text(vjust = -0.5, hjust = 0.5) +    
      labs(title = "Cumulative Paid Claims ($)",  
           x = "Variable",  
           y = "Cumulative Paid Claim",   
           color = "Loss_Year")  
  })  
  
  observe({  
     
    wb <- createWorkbook()  
    
    addWorksheet(wb, "sheet1")  
    
    
    
#Create Loss Year Column  
    loss_year <- unique(data.frame(Loss_Year = excel()[, 1]))  
    writeData(wb, "sheet1", loss_year, xy = c("A", "3"))  
    
#Create Development Year row header  
    DY <- unique(data.frame(Development_Year = excel()[,2]))  
    DY_tail <- tail(DY$Development_Year, 1)+1  
    writeData(wb,"sheet1",as.data.frame(t(c(DY$Development_Year,DY_tail))),  
              xy = c("B", "2"),colNames = TRUE)  
    saveWorkbook(wb, "testing.xlsx", overwrite = TRUE)  

    testing <- reactive({  
      data.frame(read_excel("testing.xlsx"))  
    })  
    
    #column Header Values for excel.xlsx  
    e_column1 <- excel()[,1]  
    e_column2 <- excel()[,2]  
    
    r <- 2  
    c <- 1  
    while(c+1 <= ncol(testing())-1){  
      while(r <= nrow(testing())){  
        triangle_input <- sum(excel()[e_column1 == testing()[r,1] & e_column2 <= testing()  [1,c+1],][,3])  
        writeData(wb, "sheet1", triangle_input, xy = c(c+1, r+2))  
        r <- r+1  
      }  
      c <- c+1  
      r <- 2  
    }  
    saveWorkbook(wb, "testing.xlsx", overwrite = TRUE)  
    
    #Filter the repeated value at the end  
      
    
    filtered_triangle <- t(data.frame(read_excel("testing.xlsx")))  
    filtered_triangle <- apply(filtered_triangle, 2, function(x) ifelse(duplicated(x), NA, x[!duplicated(x)]))  
    filtered_triangle <- apply(filtered_triangle, 2, function(x) ifelse(duplicated(x), NA, x[!duplicated(x)]))  
    filtered_triangle <- t(filtered_triangle)  
    addWorksheet(wb,"sheet2")  
    writeData(wb,"sheet2",x = filtered_triangle)  
    saveWorkbook(wb, "testing.xlsx", overwrite = TRUE)  
    
    addWorksheet(wb,"sheet3")  
    writeData(wb,"sheet3",x = filtered_triangle)  
    saveWorkbook(wb, "testing.xlsx", overwrite = TRUE)  
    
    origin <- read_excel("testing.xlsx","sheet2",skip = 1)  
    origin[] <- lapply(origin,as.numeric)  
     
    updated_origin <- read_excel("testing.xlsx","sheet3",skip = 1)  
    updated_origin[] <- lapply(updated_origin,as.numeric)  
    
    r <- 1  
    c <- 2  
    while(c <= ncol(origin)-1){  
      while(r <= nrow(origin)){  
        
        column_sum <- sum(origin[,c],na.rm = TRUE)  
        non_na_indices <- which(!is.na(origin[, c]))  
        
        column_divide <- sum(origin[non_na_indices,c-1],na.rm = TRUE)  
        
        #PS: [[1]] is use to extract the first value from the tibble  
        multiply <- as.numeric((read_excel("testing.xlsx","sheet3",skip = 1)[r,c-1])[[1]])  
        
        
        if(is.na(origin[r,c])){  
          writeData(wb,"sheet3",x = round(column_sum*multiply/column_divide,2),xy = c(c,r+2))  
          
          saveWorkbook(wb, "testing.xlsx", overwrite = TRUE)  
        }  
        r <- r+1  
      }  
      c <- c+1  
      r <- 1  
    }  
    
    r <- 1  
    c <- ncol(origin)  
    while(c <= ncol(origin)){  
      while(r <= nrow(origin)){  
        if(is.na(origin[r,c])){  
          estimate <- input$tail_factor*as.numeric((read_excel("testing.xlsx","sheet3",skip = 1)[r,c-1])[[1]])  
          writeData(wb,"sheet3",x = estimate,xy = c(c,r+2))  
          
          saveWorkbook(wb, "testing.xlsx", overwrite = TRUE)  
        }   
        r <- r+1  
      }  
      c <- c+1  
      r <- 1  
    }  
  })  
}  



shinyApp(ui,server)  

rsconnect::deployApp('C:/Users/xxx/Documents/R-shiny-assessment')    

What I had tried:

1. deploying the app at RStudio GUI:

    library(rsconnect)
    setwd("C:/Users/xxx/Documents/R-shiny-assessment")
    rsconnect::setAccountInfo(name='xxx', token='8531DA3C486C01599C7910D22EF44CDD', secret='xxx')
    rsconnect::deployApp(appDir = "C:/Users/xxx/Documents/R-shiny-assessment",appPrimaryDoc = 'Excel_Layout.R')

error message from log:

2024-01-30T00:57:29.488156+00:00 shinyapps[11068239]: Error in rsconnect::deployApp("C:/Users/xxx/Documents/R-shiny-assessment") : 
2024-01-30T00:57:29.492800+00:00 shinyapps[11068239]:   `appDir`, "C:/Users/xxx/Documents/R-shiny-assessment", does not
2024-01-30T00:57:29.497047+00:00 shinyapps[11068239]: exist.
2024-01-30T00:57:29.501337+00:00 shinyapps[11068239]: Calls: local ... tryCatch -> tryCatchList -> tryCatchOne -> <Anonymous>
2024-01-30T00:57:29.505803+00:00 shinyapps[11068239]: Execution halted