Currency missing from formula column

Hi, so currently on the board I’m working on, we’ve had currency added onto the formula no problem. But recently, when trying to right-click, the feature has disappeared; I’ve tried using the formula “$#,##0.00” to try and get it to show but no luck. Would anyone know why they would have stopped allowing me to add currencies?

I was unable to add “$” through the column “settings”. However, I went to the column summary at the bottom of the group and clicked on the number, a pop-up window showed up, from where I was able to add “$” to the column.