WPForms is a good plugin, and most "not sending email" advice for it is the same generic SMTP checklist you have already read. So let's skip that and start with the three failures that are specific to WPForms, all of which share one property: the visitor sees a success message, and you receive n...
Source: [Dev.to](https://dev.to/artem_meleshkin_0c4e0a675/wpforms-not-sending-email-notifications-three-ways-leads-vanish-quietly-4dhh)