We have had some issues with UXi® notification emails not being delivered. Basically what is going on is that the Email Service Providers (ESP) like yahoo, aol, google, have started tightening their Domain-based Authentication, Reporting and Conformance (DMARC) policies in regard to handling email in order to help reduce spam.
The main issue that is effecting us is that you can only send email from the domain (in our case uxi.io) that your server is in. This is the part that can get a little confusing... All of our UXi® V2 sites send email through our Mailgun servers. Our Mailgun server for UXi® is in the domain uxi.io. It doesn't matter what the client's domain is in this case. Since we use the mail server that is in the uxi.io domain, we have to configure the email coming out of UXi® so that the ESPs see that it is coming from the uxi.io domain. That's why we have to use firstname.lastname@example.org in the "from" address in our form notifications. That wasn't originally the default in UXi® so we did have more bounces than usual while we were getting all that sorted out.
So, bottom line, if the notifications are configured with email@example.com in the from field on form notifications, things should work fine. If you do notice something not going through, notify SWAT ASAP so we can look into it.