Dear sir/madam, I would like to remove the top header line

Dear sir/madam,

I would like to remove the top header line where it says:
"From TheCakeria.com (info@...)"
As seen on this image: https://premium.wpmudev.org/wp-content/uploads/2011/05/e-newsletter-macro-view.png

Apparently there is no option for that, and it does not make any sense why there even is such a line on a newsletter.

Best regards,

Il Ne