I need further assistance on this problem as I'm really stuck on getting this to work and I won't normally post a thread if I can find an online solution I'll list down below what I did to check if configuration are wrong.
Initially I tested all the email functions from the mass mailer to the registration and everything works fine, but the problem is outlook wasn't getting mails. So I opted using mandrill smtp.
Suddenly the registration emails are not sending, I tried debugging on what could be the problem. I first started testing joomla private messaging and to my surprise the emails are being sent by mandrill. Then I tried the mass mailer and with a little delay it also sent which is great to know cb passes to mandrill too. However when I try the registration it doesn't send. Finally I tried the resend confirmation button on the users and finally the mail did send!.
I'm now a little bit sure than this is not a mandrill issue anymore and I need to change something with the registration configuration/codes but I have no idea what.
I've attached a screen shot.