If you have a WordPress website, chances are that you also have a contact page, where you ask your customers or prospective customers to fill out the form for various reasons. Regardless of those reasons, you NEVER want to miss an incoming request for contact, because it is most likely vital to your business.

We recently found an issue during our routine maintenance checks, where almost all of our clients were not receiving email notifications. When we investigated, we found an error that had occurred between the Postman SMTP plugin and Google Gmail API — Bad Request(invalid_grant). We had to re-authorize access to the Google Gmail API for it to work again. It’s not clear at this time why the authorization was revoked.

WordPress out of the box functionality uses the PHP mail function to send email, which is how you would get a notification when someone fills out the contact form. This function is part of the software that runs on the Web Server that hosts your website (most likely Apache or Windows Server). The problem with PHP mail is that it sends email that is not “authenticated” and tied to any particular person (or user account), so it’s sent from “Wordpress,” which typically ends up in your junk email box.

In order to prevent this, there are several WordPress plugins that can be used to allow email/notifications to be sent from WordPress using SMTP (Simple Mail Transfer Protocol). This is the standard all email servers use to understand the incoming/outgoing email and gives you the ability to tie the email to a specific person. However, this is still not encrypted, so security can be an issue if you are just sending with SMTP.

Enter Postman SMTP plugin, which allows you to set up email notifications using OAuth v2.0 (OAuth Protocol). OAuth is a way to provide secure access to your email server API (Application Programming Interface) to send email without needing personal email user account credentials (username & password). This also means the email password can change without affecting access to the API.

While Postman SMTP is one of the best SMTP Mail plugins available, it is not flawless, and there are other systems downstream (at Google) that can sometimes impact your ability to get notifications.

If you would like to know more or be kept up-to-date with how regular website hosting maintenance can benefit your company, contact [email protected].