Noise Removal not as previewed

[Chris P]

I have a short clip that I am trying to remove some noise from.
I found Audacity and tried some experimentation. Once I figured out how it works the feature I need is "Noice Removal".
I selected the sample of noise and ran a preview. Much to my astonishment the noice is gone. Worked great.

At this point I click "Remove Noise" to apply the settings to the file. The resulting file however the voices are distorted and tinny sounding. Nothing like the perfect preview. Whats up with that? I fail to understand why the final output is not the same as the preview?

Help please as I need to get this audio to someone soon.