Magento2.2 Emails not sending with guest orders

Question

So I've been searching the internet for a couple of days now, and I can't seem to find something that is relevant for me.

When a customer places an order with an account everything is fine. But when a customer chooses to continue without an account no invoice email is being send. The backend profides a "The order confirmation email is not sent" message, but I can't seem to find any errors in the var/log directory.

Things that i've tried:

• Resetting the guest order email template
• Changing it to the same email template as the default order
• Turning some odd options on/off (people claimed that if you'd disable x it would work)

Here is an image of the current setup (Stores > Configuration > Sales > Sales Emails in the Default Config)

I don't know where the error lays, because all emails are not sending to non registered users. Track and trace, invoice, order, newsletter ect.

Server info: Ubuntu 18.04 with Nginx and php 7.1 running Magento 2.2.2

Any help / thoughts / hints would be appreciated.

Stephan

Answer 1

So the issue, like usually wasn't Magento's fault. Our server HELO reply was localhost.localdomain, because of incorrect sendmail configuration.

In the /etc/hosts file I moved our domain name to the first position, and after that the localhost.localdomain.

(The guest emails where placed with an email address that was aggressive with spam)