We have the issue that for three of our four campaigns emails are shown as sent, but the opening rate is zero so we assume that the emails are not actually being sent.
We have checked that [email protected] is approved as an email account in our Amazon settings.
What more can we do now??
Thank you for letting us know about this, it's possible that the email "[email protected]" is not added yet to one of your Marketplace country. It is required that this email gets added to every Marketplace country.
Looking at your Hunts I can only see UK Marketplace that shows an Open rate, however Spain, Italy and France doesn't have any, so it's more likely that these Marketplaces doesn't have the email "[email protected]" added yet to your Approved Senders list.