Error related to check_container_alive when publish a shiny app to shinyapps.io

Question

I have designed a shiny app. When I tried to publish this app on shinyapps.io, I got the following error message.

Error: Unhandled Exception: Child Task 958419875 error: Unhandled Exception: Timeout waiting for '_check_container_alive' after 0:00:30 Execution halted

I have used shinyapps.io to publish other shiny apps, but this is the first time I encountered this error. The only thing I can think of for now is it is the first time I used an R package, shinyStore, not from CRAN, but from github. I am wondering if this may casue some issues.

Below is the R code. Please let me know how I can solve this issue.

### This script creates an example of using the shinyStore package

# Load packages
library(shiny)
library(shinyStore)

ui <- fluidPage(
  headerPanel("shinyStore Example"),
  sidebarLayout(
    sidebarPanel = sidebarPanel(
      initStore("store", "shinyStore-ex1"),
      textInput(inputId = "Text1", label = "Enter some texts")
    ),
    mainPanel = mainPanel(
      fluidRow(
        numericInput(inputId = "Number1", label = "Enter a number", value = NA),
        sliderInput(inputId = "Slider1", label = "Pick a number", min = 0, max = 100, value = 50),
        actionButton("save", "Save", icon("save")),
        actionButton("clear", "Clear", icon("stop"))
      )
    )
  )
)

server <- function(input, output, session) {
  observe({
    if (input$save <= 0){
      updateTextInput(session, inputId = "Text1", value = isolate(input$store)$Text1)
      updateNumericInput(session, inputId = "Number1", value = isolate(input$store)$Number1)
      updateSliderInput(session, inputId = "Slider1", value = isolate(input$store)$Slider1)
    }
    updateStore(session, name = "Text1", isolate(input$Text1))
    updateStore(session, name = "Number1", isolate(input$Number1))
    updateStore(session, name = "Slider1", isolate(input$Slider1))
  })
  
  observe({
    if (input$clear > 0){
      updateTextInput(session, inputId = "Text1", value = NA)
      updateNumericInput(session, inputId = "Number1", value = NA)
      updateSliderInput(session, inputId = "Slider1", value = 50)
      
      updateStore(session, name = "Text1", value = NA)
      updateStore(session, name = "Number1", value = NA)
      updateStore(session, name = "Slider1", value = 50)
    }
  })
}

shinyApp(ui, server)

Update

After several days, I tried to published the app on shinyapps.io again with the same code, and it worked. Now my guess is there were some connecting issues between me and shinyapps.io, or shinyapps.io had some difficulties to install the shinyStore package. If someone can offer an explanation on this error message, I will accept that answer and reward the bounty.