Re: Birthday Candles won't go on Birthday Cake, Cake keeps disappearing
When the option to add candles is greyed out, it usually means that the cake is not in the right place on the surface (counter, table) it was placed. You have to move it around a little on the surface when that happens until you find the right spot for the option to be active. But the cake should not disappear, so you probably have something else going on.
If you are playing on a Mac or PC and are using any mods that concern food like CC recipes, more servings, etc., then I would suspect one of them might be the cause, but it could be other mods too. To find out, you should try moving your mods folder to your desktop then test the game to see if it still happens. If it doesn't then you'll have to test your mods to find the one causing your problem. If it does happen without mods in the game, then try a game repair through Origin or the EA App, whichever one you use.
Hope this helps.