File selection window not appearing on Shiny server (

In my Shiny app on, a user can select a file from his/her machine. A pop-up window normally appears for the user to navigate to and select the required file. This works fine locally on my own machine, but fails on the server. Instead, the following message is produced:

ERROR: An error has occurred. Check your logs or contact the app author for clarification.

From viewing my file logs for my app, it appears that the file/directory or the connection cannot be opened

Warning in file(con, "rb") : cannot open file 'öáµZU': No such file or directory

Warning: Error in file: cannot open the connection

My app is available at HACSim: Haplotype Accumulation Curve Simulator

but there are few other bugs to work out.

Simply click "RUN SIMULATION" and then navigate over to the Sub interface. Click "Run" and the error will be reproduced ()rather than a popup window appearing).