Why can't I get an email to mail easily?

I'm a leader on a larger challenge, and yet, every single I I TRY to put out an email to a current member, I often have to hit the send button 3 to 7 times. WHY? The email (MFP only of course using MFP) is correct. Is there a setting I am missing?

ALL the emails are going to current members on our MFP challenge only. NO One who's not signed up and active within the challenge.

Its so beyond frustrating.

THANKS for all suggestions.