If you have a busy site with notifications emails, READ THIS !

If you have (or expect to have) a large ammount of email (notifications from Anspress), try this: Email Queue. The emails are stored in a queue and they are send in CRON batches (configurable).

Works GREAT for me for one week now. Not a single problem. That way you can overcome server load and also hosting email sending limits (for example in shared hosting, 1000 emails per hour in my case). It has several configurations to tune email sending.

https://wordpress.org/plugins/smtp-mailing-queue/

Test of cource if it works for you. I hope i have helped.