mailchimp API is in but newsletter sign up still not working

1. ME:
Hi. I am not a developer by any means but I have created several wordpress sites in the past and understand some basic html. I don't touch CSS - frankly it's stressful and scary and the two times I tried it had to have my site restored from a backup. This is to say I can understand instructions if they are clear.

2. THEMEFUSE SUPPORT:
To put it in a nutshell their support attempts through the several tickets have helped me get pretty much nowhere with the issues I am having.

3. $:
I cannot afford to hire a developer.

4. WPMUDEV:
Perhaps WPMUDEV can help me get on track. We will soon see.

5. IMPORTANT INFO:
Site: http://www.missionimpactalliance.org
Username: -----
Password: -----
(Available on request should need you to see the back end)

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6. QUESTION #3

I set up a mail chimp account and put the API key in the newsletter settings in the toolbar under "Philanthropy"

However, when attempting to sign up for the newsletter on the homepage, it still does not work