Sending emails with Return-path installation in Magento 2 is so necessary for users. Because these Return-path emails default automatically to unrecognized address, they will be spam and go to spam filters. It means that the people whom you want to send the message can not receive it. It is so serious if the email is important.
To avoid this situation that your emails are no more considered as spam, you should Configure return-path emails. Setting Configure return-path emails in Magento 2, the system can be aware of problems and resolve them by SPF settings or SAV (Sender Address Verification).Then, it takes for granted that your emails will become valid, no failed anymore.
There are 5 main steps:
Mail Sending Settings
It comes to the end of tutorial: Magento 2: Configure Return-path email.