Rshiny Sending an Email with mailR | jCall Error - r

Question

Below is the mailR code I have running on the server side of an RShiny app that I am building. The aim of this app is to send an email when a certain occurrence happens in the financial markets. When I run this code on its own in a separate script (not in a RShiny app) it runs fine. When run in the RShiny app, the app crashes with the error below.
sender <- "FROM#gmail.com"
recipients <- c("TO#gmail.com")
body.string <- "words words words words words punchline"
send.mail(from = sender,
to = recipients,
subject = "***STOPLOSS ALERT***",
body = body.string,
smtp = list(host.name = "smtp.gmail.com", port = 465,
user.name = "FROM#gmail",
passwd = "******", ssl = TRUE),
authenticate = TRUE,
send = TRUE)
Error Message:
Warning in if (file.exists(body)) body <- readChar(body, file.info(body)$size) :
the condition has length > 1 and only the first element will be used
Warning: Error in .jcall: java.lang.NoSuchMethodException: No suitable method for the given parameters
Stack trace (innermost first):
56: <Anonymous>
55: stop
54: .jcheck
53: .jcall
52: .jrcall
51: email$setMsg
50: send.mail
43: isolate
42: server [C:\Users\****/app.R#135]
1: runApp
Error in .jcall("RJavaTools", "Ljava/lang/Object;", "invokeMethod", cl, :
java.lang.NoSuchMethodException: No suitable method for the given parameters
Since the code works fine on its own, outside of the Shiny app, my thinking is that RShiny is somehow causing this to bug out on the lower level Java code. Any advice/tips would be greatly appreciated.

Answer 1

Can you try executing a simple code like below and tell me if you are still getting any error?
library(mailR)
library(shiny)
ui <- fluidPage(
actionButton("sendMail","Send Mail")
)
server <- function(input, output) {
observeEvent(input$sendMail,
{
sender <- "FROM#gmail.com"
recipients <- c("TO#gmail.com")
body.string <- "words words words words words punchline"
send.mail(from = sender,
to = recipients,
subject = "***STOPLOSS ALERT***",
body = body.string,
smtp = list(host.name = "smtp.gmail.com", port = 465,
user.name = "FROM#gmail",
passwd = "******", ssl = TRUE),
authenticate = TRUE,
send = TRUE)
}
)
}
shinyApp(ui = ui, server = server)