My wordpress installation was working fine all this time, until it upgraded contact form 7 to Version 4.4 now it has a configuration error.
"Contact Form 7 Plugin Error: This email address does not belong to the same domain as the site"
Try this, because it worked for me:
From: [first-name] [last-name] <donotreply@your-site.com>
Of course your-site.com is your domain and you might not have first and last names.
It's said that you to create a @mysite.com email with your host, maybe something like do-not-reply@mysite.com.
Hope that helps,