I presume you started by copying the example in the app reference.
"app.CreateEmail requires you to pass your email and password, which is required to verify you but it also creates a security issue because the password in included as plain text in the apk"
You could ask the user to type in their email and password (but would they trust your app?).
I reckon the account in the createemail and the sender in the send should be the same (or mimecast etc will reject it).
Are you getting any error messages?
(Try touching the fourth "bug" icon at the bottom of the edit screen, or the right hand debug window if using the IDE from a browser).
Regards, ah