if you check SMTP but the result is not deliver. Still sending mass emails. We are sure you will still get good results if your email list is private domain mail. Don't ditch SMTP and don't use it. The reason is that your email has a strong firewall

HOW TO GET YOUR SMTP WHEN YOUR ORDER SUCCESSFULLY PROCESSED ?

DETAIL

SMTP configuration parameters on Turbo Mailer. Configured like this you can send 200,000 emails a day

How to fix SMTP connection lost error while sending bulk email