Here is my error message in the logs of shinyapp.io. I am trying to launch a data visualization app, but cannot overcome this error. Any ideas?

2024-08-19T20:04:01.772505+00:00 shinyapps[12457920]: httpuv version: 1.6.11

2024-08-19T20:04:01.776364+00:00 shinyapps[12457920]: rmarkdown version: 2.24

2024-08-19T20:04:01.779893+00:00 shinyapps[12457920]: knitr version: 1.43

2024-08-19T20:04:01.783611+00:00 shinyapps[12457920]: jsonlite version: 1.8.7

2024-08-19T20:04:01.788113+00:00 shinyapps[12457920]: RJSONIO version: (none)

2024-08-19T20:04:01.791649+00:00 shinyapps[12457920]: htmltools version: 0.5.6

2024-08-19T20:04:01.795240+00:00 shinyapps[12457920]: reticulate version: (none)

2024-08-19T20:04:01.798920+00:00 shinyapps[12457920]: Using pandoc: /opt/connect/ext/pandoc/2.16

2024-08-19T20:04:01.802550+00:00 shinyapps[12457920]:

2024-08-19T20:04:01.806497+00:00 shinyapps[12457920]: Starting R with process ID: ’31’

2024-08-19T20:04:01.809904+00:00 shinyapps[12457920]: Shiny R Markdown document starting …

2024-08-19T20:04:01.813505+00:00 shinyapps[12457920]:

2024-08-19T20:04:01.817119+00:00 shinyapps[12457920]: Listening on http://127.0.0.1:40571

2024-08-19T20:04:03.729675+00:00 shinyapps[12457920]: Running on host: bbfe5430db3e

2024-08-19T20:04:03.734435+00:00 shinyapps[12457920]: Running as user: uid=10001(shiny) gid=10001(shiny) groups=10001(shiny)

2024-08-19T20:04:03.738399+00:00 shinyapps[12457920]: Connect version: 2024.05.0

2024-08-19T20:04:03.742016+00:00 shinyapps[12457920]: LANG: C.UTF-8

2024-08-19T20:04:03.745546+00:00 shinyapps[12457920]: Working directory: /srv/connect/apps/rfct_mismatches_app

2024-08-19T20:04:03.749347+00:00 shinyapps[12457920]: Using R 4.3.1

2024-08-19T20:04:03.774412+00:00 shinyapps[12457920]: R.home(): /opt/R/4.3.1/lib/R

2024-08-19T20:04:03.778386+00:00 shinyapps[12457920]: Content will use current R environment

2024-08-19T20:04:03.782783+00:00 shinyapps[12457920]: R_LIBS: (unset)

2024-08-19T20:04:03.786889+00:00 shinyapps[12457920]: .libPaths(): /usr/lib/R, /opt/R/4.3.1/lib/R/library

2024-08-19T20:04:03.792212+00:00 shinyapps[12457920]: shiny version: 1.8.0

2024-08-19T20:04:03.795796+00:00 shinyapps[12457920]: httpuv version: 1.6.11

2024-08-19T20:04:03.799290+00:00 shinyapps[12457920]: rmarkdown version: 2.24

2024-08-19T20:04:03.803036+00:00 shinyapps[12457920]: knitr version: 1.43

2024-08-19T20:04:03.806825+00:00 shinyapps[12457920]: jsonlite version: 1.8.7

2024-08-19T20:04:03.810256+00:00 shinyapps[12457920]: RJSONIO version: (none)

2024-08-19T20:04:03.814471+00:00 shinyapps[12457920]: htmltools version: 0.5.6

2024-08-19T20:04:03.818152+00:00 shinyapps[12457920]: reticulate version: (none)

2024-08-19T20:04:03.822087+00:00 shinyapps[12457920]: Using pandoc: /opt/connect/ext/pandoc/2.16

2024-08-19T20:04:03.825896+00:00 shinyapps[12457920]:

2024-08-19T20:04:03.829695+00:00 shinyapps[12457920]: Starting R with process ID: ’48’

2024-08-19T20:04:03.833863+00:00 shinyapps[12457920]: Shiny R Markdown document starting …

2024-08-19T20:04:03.837979+00:00 shinyapps[12457920]:

2024-08-19T20:04:03.841574+00:00 shinyapps[12457920]: Listening on http://127.0.0.1:35469

2024-08-19T20:04:03.845202+00:00 shinyapps[12457920]: Warning: Error in if: argument is of length zero

2024-08-19T20:04:03.849214+00:00 shinyapps[12457920]: 74: ui

2024-08-19T20:04:03.853091+00:00 shinyapps[12457920]: 17:

2024-08-19T20:04:03.856514+00:00 shinyapps[12457920]: 15:

2024-08-19T20:04:03.860132+00:00 shinyapps[12457920]: 13: fn

2024-08-19T20:04:03.864240+00:00 shinyapps[12457920]: 8: retry

2024-08-19T20:04:03.867884+00:00 shinyapps[12457920]: 7: connect$retryingStartServer

2024-08-19T20:04:03.871610+00:00 shinyapps[12457920]: 6: eval

2024-08-19T20:04:03.875278+00:00 shinyapps[12457920]: 5: eval

2024-08-19T20:04:03.878713+00:00 shinyapps[12457920]: 4: eval

2024-08-19T20:04:03.882439+00:00 shinyapps[12457920]: 3: eval

2024-08-19T20:04:03.886054+00:00 shinyapps[12457920]: 2: eval.parent

2024-08-19T20:04:03.889727+00:00 shinyapps[12457920]: 1: local

I have changed all my if (cond) to add a case where the condition has a length 0 vector.