Email Customizer send over SMTP instead of PHP
I reviewed the server logs and looked for the emails sent from firstname.lastname@example.org. Based on the logs, most of the emails are sent via a script:
2020-10-26 09:23:13.918807 52772 H=(c27927.sgvps.net) [127.0.0.1]:47136 I=[127.0.0.1]:25 Warning: SITEGROUND: "Letsleds.nl" <email@example.com> : This message was sent via script. The details are as follows: PWD=/home/customer/www/letsleds.nl/public_html REQUEST_URI=/?wc-api=Wc_Pay_Gateway_Exchange SCRIPT_FILENAME=/home/u44-udpxx47wed6k/www/letsleds.nl/public_html/index.php REMOTE_ADDR=126.96.36.199 .
2020-10-26 09:24:43.510689 53675 H=(c27927.sgvps.net) [127.0.0.1]:35112 I=[127.0.0.1]:25 Warning: SITEGROUND: Laurens Broumels <firstname.lastname@example.org> : This message was sent via script. The details are as follows: PWD=/home/customer/www/letsleds.nl/public_html REQUEST_URI=/wp-json/contact-form-7/v1/contact-forms/10513/feedback SCRIPT_FILENAME=/home/u44-udpxx47wed6k/www/letsleds.nl/public_html/index.php REMOTE_ADDR=188.8.131.52 .
That means, that you are using the built-in PHP mail function on the server to send these emails and they lack authentication layers. That is also the most likely reason why the emails are being treated as SPAM by major providers. As such, in order to resolve that, the best thing you can do is configure your application to send emails over SMTP. Since I can see, that your website is built on WordPress, you can check our article on how to configure the application to work over SMTP here:
This will add an additional authentication layer to the emails sent by your application, it will increase their deliverability and the messages will be less likely to be treated as SPAM by major email service providers.
Please instruct how to add these setting to the plugin.