I have same problem.
My contact from is very simple.
FORM
Name:
[text* your-name]
Email:
[email* your-email]
but
Mail
add-header :[your-email]
Invalid mailbox syntax is used.
Mail 2
sender:[your-email]
Invalid mailbox syntax is used.
and…
Mail is sent even if the Name is blank.
Mail is sent even if the Email is blank.
