Can't add external links in nav menu

Question

First, forgive me as I'm not a professional programmer. I have access to our CMS as our company's web content manager, however our marketing agency handles heavy duty programming and design.

We recently updated our ExpressionEngine to version 2.5.5. Since then, I'm not able to utilize one of the tools that I could prior to that in the editor. When publishing a new page, there is an option for me to add External Links to appear in a navigation menu. There are two fields to add the headline text and the corresponding link. Below those fields is a '+' sign to add another headline/link. However, when I click this '+' sign, nothing happens. This should add more rows to this nav menu.

I'm hoping this is a simple fix. We just transitioned to a new agency so typically I'd ask them for help, but they're still familiarizing themselves with the system and right now I'm just trying to get a head start on this particular issue.

Any help you can give me is greatly appreciated. I apologize in advance if this request isn't appropriate for this forum!

EDIT: here is a screenshot: http://i.stack.imgur.com/zsVgP.png

Answer 1

Adding rows of content in a loop sounds a lot like Matrix.

1. Go to AddOns and choose Fieldtypes. See if you see a listing for Matrix. If so, click on it's name.
2. Check the license number is there and click Submit.

I know when I upgrade the site, and Matrix, sometimes I need to click Submit or else it doesn't initialise. Catches me out every few years.. If you're lucky, it's something small like this otherwise a discussion with your agency is in order.