Creating overlay for video issue

[FPConsumer]

I am trying to create an overlay for a video podcast. I have done this before in Illustrator but it is not working right now. This is my process:

1. Image as background

2. Create squares on top of image

3. Group Squares

4. Highlights all objects

5. Create transparency clipping mask (invert mask and uncheck clip)

The result is that it does create transparency in the squares but I need it to be fully transparent and not have the background image still visible. I have attached an image of the end result. Any help is greatly appreciated!

[Doug A Roberts · Accepted solution]

What is the fill of your squares? If it's 100 K in a CMYK doc, for instance, that isn't pure black for the purposes of opacity masks.

[FPConsumer]

I filled the squares with this color #BFE2C4 in and RGB setup. 

Now that I thought about your question, I tried filling the squares black and it worked how I wanted it to. I realized that I had used white for the squares last time. I didnt think the color had an affect on it. Thank you for your help!

[Doug A Roberts]

In an opacity mask, RGB black is fully opaque and RGB white is fully transparent (unless inverted) -- colours in-between produce varying transparency.