xml tag in preview rather than text from email body

Hi! When I send an email to a friend the xml tag is showing up instead of the body of the email in the preview on their android phone (i.e. they see

Is it only happening to this one receiver? When you reply to their emails, is the same thing happening?

You could try sending in Plain Text rather than HTML. When composing a new email or reply, select Plain Text from the menu.