Unable to send message;Reason:550 5.4.6Mail rate exceeded limit

Unable to send message;Reason:550 5.4.6Mail rate exceeded limit

I am trying to send a Survey Monkey to my friends and neighbors for my HOA.  There are 78 email addresses.  I broke tht email into 4 separate 4 emails.  25, 25, 25 and 3 email addresses a piece.  When I try and send anything I get the following error.

Unable to send message;Reason:550 5.4.6Mail rate exceeded limit

I am not trying to SPAM anyone.  What is this error for?