I can see you also reached out to our chat support about this, and would like to share our answer here in the community as well. After taking a look at you account we were able to see your campaign is actually a Welcome Email. I apologize Welcome Emails only get sent out to new contacts that sign-up through a sign-up form. In your case we would suggest recreating this email in Automated Email Series instead. This type of Autoresponder will allow your email to be sent whether contacts are added manually in your account or through a sign-up form.