If you check your open rates from the campaign manager, and you notice that you have sent a good amount of emails and the open rate says 0, this is because you have either mis-typed your amazon seller email address or its not an approved or registered email user.
To fix this, go to
ACCOUNTS SETTINGS<MARKETPLACES SETTINGS
Check that the email address you entered in the Amazon Sellers Email address box is spelled correctly. If it is, make sure its either a registered or approved sender in your seller central.
To view the approved/registered email address in Amazon, click
Check the Registered senders email or approved senders to make sure that the email address entered in FeedbackWhiz matches exactly. Then click Done!