eNewsletter not sending out emails


Thew newsletter plugin is not sending out emails.

I first tried the phpMail. - Send Now - it went thru 16 subscribers on my email list (progress bar updated) but didnt get anything in my 2 email test accounts (checked spam folders)

I then switched settings to SMTP - test coneectection works and i receive test emails

However when i try to send newsletter - it says error sending - check email settings ????

I cannot understand why - please help urgently. I have granted support access if need be