You need an SMTP plugin that sits between HMS Testimonials and Google, delivering that mail. Try mine : https://wordpress.org/plugins/postman-smtp/
If that is the case, I would assume the contact forms on our site would require that as well. Can you shed some light on why we are able to receive emails from the contact forms, but not this plugin?
The content of the email is enough to tips the scale from suspicious to rejected.
That was my initial thought as well, so I made the tests as real as possible to see if I could trick it, but I did not succeed. Thank you for recommending your plugin. I always like to make sure I have checked off any other possible issues or settings before adding more functionality to a site to make sure we are providing the best performance possible. I greatly appreciate you taking the time to provide input and your experience.
Gmail is one of the easier ones to setup. As long as the From: address in the message is your own gmail address, and you use the SMTP server smtp.gmail.com, you should be bulletproof.
The Email Log in the plugin will help show you what’s wrong with your site, regardless. It’s difficult to say 100% what the issue is when you have no evidence.
Simply installing any SMTP plugin and configuring it correctly solves most WordPress email problems. The remainder are usually caused by poorly setup domains – those missing SPF, DKIM, etc. (not something you have to worry about with an @gmail.com address).
