Sendmail not working in a standalone App Designer application on MAC only

Hello,

I've made an app designer app where users can save some information (generated in the app) and then e-mail an excel spreadsheet with that information to a specified e-mail address. I have a throw-away g-mail account with less secure apps turned on which has allowed the successful transmission of the e-mails thus far. I've recently compiled the app for MAC use on OS X, and started running into some errors.

1. The app runs just fine - sends the e-mail and everything great when it's in MATLAB App Designer.
2. The app runs just fine, except for sending the e-mail when it's in its standalone desktop application for MAC (works fine and sends emails in the stand-alone app on PC)

The line of code that throws the error is the first time the preference is set:

setpref('Internet','SMTP_Server','smtp.gmail.com');

Does anyone know if the preferences are called something different or become un-set-able in a desktop app for MAC OS X?

I'd love to get these e-mails running.

Any suggestions would be appreciated.

Thanks