Category Subscription Link Not Showing

Can't seem to get the category subscription link to appear. The blog is set to a single category in the Joomla menu. All the settings I can find are set to show the category subscription link but it doesn't show.

When I change the menu item type in Joomla to All Categories it then appears. I don't want this setting however because I will be having multiple blogs for different clients and each will be by invitation only.

Thanks,
Mike