Newly install shiny not rendering layout or image correctly

[naturofix]

I've recently had rstudio-server and shiny-server installed on a linux server.
When running a shiny app that is working elsewhere the layout does not render properly. All tabs are seen as a vertical list of text.
Images are also no rendered.
I get the same result whether I run the app in rstudio-server or in shiny-server

The shiny-server example with the histogram only shows the numericInput box allowing the selection of the number of bins, but does not show the actual plot.

Sys.info()
sysname
"Linux"
release
"4.9.0-8-amd64"
version
"#1 SMP Debian 4.9.144-3.1 (2019-02-19)"
nodename
"adl1-dmz-lin-app03"
machine
"x86_64"

Any advice would be greatly appreciated

shiny-server.log
[2019-02-27T11:06:28.501] [INFO] shiny-server - Shiny Server v1.5.9.923 (Node.js v8.11.3)
[2019-02-27T11:06:28.503] [INFO] shiny-server - Using config file "/etc/shiny-server/shiny-server.conf"
[2019-02-27T11:06:28.565] [WARN] shiny-server - Running as root unnecessarily is a security risk! You could be running more securely as non-root.
[2019-02-27T11:06:28.571] [INFO] shiny-server - Starting listener on http://[::]:3838
[2019-03-18T11:48:10.616] [INFO] shiny-server - Created bookmark state directory: /var/lib/shiny-server/bookmarks
[2019-03-18T11:48:10.636] [INFO] shiny-server - Created user bookmark state directory: /var/lib/shiny-server/bookmarks/shiny
[2019-03-26T22:21:06.633] [INFO] shiny-server - Shiny Server v1.5.9.923 (Node.js v8.11.3)
[2019-03-26T22:21:06.638] [INFO] shiny-server - Using config file "/etc/shiny-server/shiny-server.conf"
[2019-03-26T22:21:06.726] [WARN] shiny-server - Running as root unnecessarily is a security risk! You could be running more securely as non-root.
[2019-03-26T22:21:06.732] [INFO] shiny-server - Starting listener on http://[::]:3838

[andresrcs]

I have two ideas that you can try, to rule out the most common issues, first, double check that you have proper execution permissions and ownership on this folder srv/shiny-server for shiny user then, also try installing the Cairo package install.packages("Cairo") for adding a graphics device.

Also, besides the shiny-server logs, have you checked the logs for the app?