Android Question send an email in the background

You cannot use the user's email settings without user intervention.

Start here: https://www.b4x.com/android/forum/threads/b4x-sending-emails-with-gmail-rest-api.81736/#content

Another "background" option is to make a http call to your server and send an email from the server. This is much better than putting your smtp credentials inside the app.

Thanks !