Preparing to deploy document...DONE
Uploading bundle for document: 2545903...Warning in FUN(X[[i]], ...) :
Unable to find repository URL for package XML
You usually have this error when the repository from where you have install XML package is not found.
You should check that you have install it from CRAN, and which CRAN repo is currently set on your side. This is because I think shintapps.io will try to download from the repository you have currently setup. Check if this is an online cran repo accessible for shinyapps.io
This is some hints. I am not sure of all that but it reminds me of this