In order to use our mailing system, you must have an SMTP provider. We suggest SendGrid, but you can also use Mandrill, Mailgun or SendInBlue. For testing purposes, you can also use your Gmail account (be careful with this as you're going to get blocked very quickly).
From Xangle, you can monitor the outbound emails by going in the "monitoring" panel (in the top-right corner menu)
When sending emails through the gallery, the app will now be using your SMTP and SendGrid (if you use it) will give your metrics about these emails:
If you are using your own smtp server, and are experiencing problems, use this tool to diagnose what might be the cause of the issue: https://www.gmass.co/smtp-test
Be careful to keep your attachments not too heavy, otherwise they are going to be blocked wither by your SMTP provider or your recipient email system. Gmail attachment size limit is 25mb.
Here's the procedure to create your Api key from Sendgrid