R shiny: read ECONNRESET Error randomly occurs - r

Question

Almost the time the app works find but the error occurs randomly, and I cannot find the error trace in the apps log(/var/log/shiny-server):
An error has occurred
The application exited unexpectedly.
read ECONNRESET
The sessionInfo() is as below:
R version 3.4.3 (2017-11-30)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Debian GNU/Linux buster/sid
Matrix products: default
BLAS: /usr/lib/x86_64-linux-gnu/blas/libblas.so.3.7.1
LAPACK: /usr/lib/x86_64-linux-gnu/lapack/liblapack.so.3.7.1
locale:
[1] LC_CTYPE=en_US.UTF-8 LC_NUMERIC=C
[3] LC_TIME=en_US.UTF-8 LC_COLLATE=en_US.UTF-8
[5] LC_MONETARY=en_US.UTF-8 LC_MESSAGES=en_US.UTF-8
[7] LC_PAPER=en_US.UTF-8 LC_NAME=C
[9] LC_ADDRESS=C LC_TELEPHONE=C
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C
attached base packages:
[1] stats graphics grDevices utils datasets methods base
loaded via a namespace (and not attached):
[1] compiler_3.4.3
And there's not much info about this issue with R shiny app, maybe it's about node.js?
Thanks for any advise in advance.

Answer 1

Finally I solved it by adding below code in server.r
onStop(function() {
odbcClose(conn)
})
I query data from database frequently but I did not close it.
After adding the code to close connection the error seldom occurs.
And I also adjust the app_idle_timeout to 0 in the /etc/shiny-server/shiny-server.conf