I created this graph using ggplot2:
```{r ggplot1, fip.cap="Example graph"}
ggplot(data.frame(x = c(1, 2, 3, 4, 5), y = c(1, 4, 9, 16, 25)), aes(x=x, y=y)) +
labs(x="$x$", y="$y$") +
geom_line() + geom_point()
```
The figure caption should be "Example graph". But for some reason it's not showing. For every other graph I made, it worked perfectly fine. Here is an image.