Shiny app shows "disconnected from server" on Shiny.io even right after starting

[snailittle]

Hi. I synced a shiny app under the link
Concentration-QT Trial Simulation in Support of TQT Waiver

It runs perfectly on my personal computer, but after uploading to Shiny.io, when I run the simulation with loading dose options, i.e. loading dose administration timepoint (day) = "0, 3" and Additional loading dose (mg) on top of reference dose at each administration timepoint = "50, 50", the shinyapp reports "disconnected from server, reload".

[andresrcs]

Hi, welcome!

We don't have enough information to help you out, Could you check what your app's logs say?

[snailittle]

Here are all the logs

2021-07-09T18:13:08.319672+00:00 shinyapps[4258501]: jsonlite version: 1.7.2
2021-07-09T18:13:08.547441+00:00 shinyapps[4258501]:
2021-07-09T18:13:08.314228+00:00 shinyapps[4258501]: Running on host: bbcfc889604b
2021-07-09T18:13:08.319582+00:00 shinyapps[4258501]: LANG: en_US.UTF-8
2021-07-09T18:13:08.517329+00:00 shinyapps[4258501]:
2021-07-09T18:13:08.547442+00:00 shinyapps[4258501]: Listening on http://127.0.0.1:35645
2021-07-09T18:13:08.745439+00:00 shinyapps[4258501]:
2021-07-09T18:13:08.745441+00:00 shinyapps[4258501]: Attaching package: ‘shinyjs’
2021-07-09T18:13:08.745443+00:00 shinyapps[4258501]:
2021-07-09T18:13:08.746183+00:00 shinyapps[4258501]: The following object is masked from ‘package:shiny’:
2021-07-09T18:13:08.746184+00:00 shinyapps[4258501]:
2021-07-09T18:13:08.746185+00:00 shinyapps[4258501]:
2021-07-09T18:13:08.746184+00:00 shinyapps[4258501]: runExample
2021-07-09T18:13:08.746534+00:00 shinyapps[4258501]: The following objects are masked from ‘package:methods’:
2021-07-09T18:13:08.746536+00:00 shinyapps[4258501]:
2021-07-09T18:13:08.746536+00:00 shinyapps[4258501]: removeClass, show
2021-07-09T18:13:08.746535+00:00 shinyapps[4258501]:
2021-07-09T18:13:24.465810+00:00 shinyapps[4258501]: RxODE 1.0.8 using 8 threads (see ?getRxThreads)
2021-07-09T18:13:24.465812+00:00 shinyapps[4258501]: no cache: create with rxCreateCache()
2021-07-09T18:13:24.473201+00:00 shinyapps[4258501]:
2021-07-09T18:13:24.473202+00:00 shinyapps[4258501]: Attaching package: ‘dplyr’
2021-07-09T18:13:24.473569+00:00 shinyapps[4258501]: The following objects are masked from ‘package:stats’:
2021-07-09T18:13:24.473570+00:00 shinyapps[4258501]:
2021-07-09T18:13:24.473570+00:00 shinyapps[4258501]: filter, lag
2021-07-09T18:13:24.473202+00:00 shinyapps[4258501]:
2021-07-09T18:13:24.473570+00:00 shinyapps[4258501]:
2021-07-09T18:13:24.473891+00:00 shinyapps[4258501]: The following objects are masked from ‘package:base’:
2021-07-09T18:13:24.473891+00:00 shinyapps[4258501]:
2021-07-09T18:13:24.473892+00:00 shinyapps[4258501]: intersect, setdiff, setequal, union
2021-07-09T18:13:24.473892+00:00 shinyapps[4258501]:
2021-07-09T18:13:24.510695+00:00 shinyapps[4258501]:
2021-07-09T18:13:24.510697+00:00 shinyapps[4258501]: Attaching package: ‘gridExtra’
2021-07-09T18:13:24.510697+00:00 shinyapps[4258501]:
2021-07-09T18:13:24.511021+00:00 shinyapps[4258501]: The following object is masked from ‘package:dplyr’:
2021-07-09T18:13:24.511022+00:00 shinyapps[4258501]:
2021-07-09T18:13:24.511023+00:00 shinyapps[4258501]: combine
2021-07-09T18:13:24.511023+00:00 shinyapps[4258501]:
2021-07-09T18:13:24.540879+00:00 shinyapps[4258501]:
2021-07-09T18:13:24.540881+00:00 shinyapps[4258501]: Attaching package: ‘MASS’
2021-07-09T18:13:24.540881+00:00 shinyapps[4258501]:
2021-07-09T18:13:24.541567+00:00 shinyapps[4258501]: The following object is masked from ‘package:dplyr’:
2021-07-09T18:13:24.541568+00:00 shinyapps[4258501]:
2021-07-09T18:13:24.541569+00:00 shinyapps[4258501]: select
2021-07-09T18:13:24.541569+00:00 shinyapps[4258501]:
2021-07-09T18:13:24.601065+00:00 shinyapps[4258501]:
2021-07-09T18:13:24.601067+00:00 shinyapps[4258501]: Attaching package: ‘nlme’
2021-07-09T18:13:24.601068+00:00 shinyapps[4258501]:
2021-07-09T18:13:24.601411+00:00 shinyapps[4258501]: The following object is masked from ‘package:dplyr’:
2021-07-09T18:13:24.601412+00:00 shinyapps[4258501]:
2021-07-09T18:13:24.601413+00:00 shinyapps[4258501]: collapse
2021-07-09T18:13:24.601413+00:00 shinyapps[4258501]:

[andresrcs]

Sadly, the logs show no clue about your problem, we might need a reproducible example (reprex) illustrating your issue. Please have a look at these resources, to see how to create one for a shiny app

Chapter 5 Workflow | Mastering Shiny

Shiny debugging and reprex guide

Shiny issues can be challenging to resolve relative to other problems with your code or statistical methods. Shiny apps are often large, complex projects with interacting files. When seeking help from others it is considered polite to: First, do your best to work through RStudio's debugging tools to diagnose your issue on your own. Often those shiny logs and tracebacks are useful to others trying to help out. Second, strive to minimize the effort required to replicate your issue. You can do this with a reproducible example ("reprex"). Shiny Debugging Errors in Shiny code can be difficult to track down. If you don't know where your problem is coming from, you can track it down with some o…