flexdashboard not rendering in rmarkdown report

I am trying to generate a report using flexdashboard in a rmarkdown report. I have successfully generated a report in RStudio, but I cannot generate the same flexdashboard in Dataiku. I have selected the flex-dashboard option in snapshot and download, but they do not operate as expected.

Source code:

---
title: "test"
author: "cnl"
date: "July 15, 2019"
output: 
  flexdashboard::flex_dashboard:
    orientation: rows
---

Row
-------------------------------------

### Chart 1
```{r}
library(flexdashboard)
```

```{r}
valueBox(7)
```

### Chart 2

```{r}
gauge(8, min = 0, max = 100, symbol = '%', gaugeSectors(
  success = c(80, 100), warning = c(40, 79), danger = c(0, 39)
))
``` 

Row
-------------------------------------

### Chart 3

```{r}
gauge(94, min = 0, max = 100, symbol = '%', gaugeSectors(
  success = c(80, 100), warning = c(40, 79), danger = c(0, 39)
))
```

### Chart 4

```{r}
```

This is the file as generated by RStudio:

This is what I get when I open the downloaded file from Dataiku:

Any suggestions?