Unable to connect to worker after 60.00 seconds; startup took too long


I have a working Shiny App that queries a remote MySQL database via pool that I can run on my local machine.

The MySQL I'm querying server has whitelisted shinyapps.io IP addresses.

When I deploy this app to shinyapps_io, why do I get the following error and what are some troubleshooting steps?

enter image description here

Here are my files:



pool <- dbPool(
  drv = RMySQL::MySQL(),
  dbname = "some_name",
  host = "some.host.com",
  username = "some_username", 
  password = "password"
onStop(function() {


shinyServer(function(input, output, session) {
  output$data_table <- renderDataTable({
    DT::datatable(pool %>% tbl("small_data") %>% collect())




Hi, just to confirm the Host address in the real app is an Internet IP or URL, not the internal VPC IP or URL.


Hi Edgar, and thanks for asking.

I confirmed with my system admin that the host IP I'm using to query the database is indeed a public IP (, and it's a FQDN.

Any ideas what might cause this behavior?


UPDATE: It works now. My system admin added a port, and that fixed the issue.

For anyone down the line that is running into this issue, there are the steps I recommend:

  1. make sure your shinyapp works locally
  2. if you get deployment errors on shinyapps.io, make sure:
  • your database has whitelisted shinyappsio IP addresses
  • your host is an external, public IP or URL and not an internal one
  • some institutions have very guarded firewalls. Try adding a port to your database.

I hope this helps someone down the line!

pool <- dbPool(
  drv = RMySQL::MySQL(),
  dbname = "some_name",
  host = "some.host.com",
  username = "some_username", 
  password = "password",
  port = 1234567