Issue with using datetext() function in Appian Portals

Hi everyone,

I've encountered an error when using datetext() function in Portals saying:

Expression evaluation error [evaluation ID = CMISK] at function 'datetext' [line 5]: Expression evaluation error : The function 'datetext' is unavailable.

So, my question is if this is a known issue or am I doing something wrong because function list says that datetext() is available in Portals. I am attaching interface code that I published as portal and used to isolate this issue.

{
  a!sectionLayout(
    label: "Section",
    contents: {
      a!textField(value: datetext(now(),"yyyy/MM/dd"),
      readOnly: true()
      )
    }
  )
}