Not receiving emails from Exp:resso Store 1.65 when order completed. Nether order conformation to the buyer or the notification to the store manager are generating, you can see the order when I login. It seemed to start when I migrated the site to hosting on nexcess.net. Any ideas, lost.
Per Ian's advice in the comments, I highly recommend using Sendgrid or a similar service for sending email. Sending email directly from your own server is highly unreliable, and likely to get caught in a spam filter or even outright blocked in this day and age. Sendgrid is free for up to 200 emails per day, so there is really no reason not to use it.