App works on but not always on AWS EC2 Instance

I have developed an app and published via for development and testing while a third party manages the project IT and production-version app server. The third party set up a link between the master GitHub branch to auto-publish to the site they created, located on an AWS EC2 instance.

All works well on my development version (including log files, checked these), but on the version the AWS version, the app errors out sometimes when specific variables are selected from a dropdown menu of variables. The AWS app fails/disconnects from the server, but again, this is not consistent and seems to work on Safari consistently, but Chrome, Firefox, Edge and IE are all sporadic in performance.

I have tested this on the following OSs: Windows, Ubuntu, Mac. And the following browsers: Firefox, Chrome, Microsoft Edge, IE. I know that browsers cache info that can cause issues, but the problem persists even in 'incognito' or 'private' windows.

I have reviewed the log file and server config for the AWS app and compared to the log file (I cannot figure out how to get the server config). The error messages in the AWS app log file that concern me and make me think it may be an R environment issues are the following (which are not present in the log):

Warning: Error in sum: invalid 'type' (list) of argument
Warning: Error in : Can't find column `` in `.data`.

My questions are:

  • Any ideas on what could be causing the performance difference between the app and the AWS app?

  • How can I review the server config file for to compare to the AWS Shiny Server config?

Thank you in advance for your help.