Norton Anti-Spam Filtering Marketing Messages

I am using Norton Business Suite Version 20.4.0.40 and Outlook version 14. 

Recently, the messages we mail to subscribers on our website have been

filtered by Norton AntiSpam. We've added the address we mail from to the

allowed list in our own Norton, but we fear that many of our subscribers are

now not seeing our messages because they have been filtered into their

spam folder. 

 

We're wondering if you can give us any insight into WHY are messages were

filtered in the first place? Is it based on the content of the emails, or on some

kind of blacklist? We're also wanting to know what steps our subscribers could

take to make sure these messages end up in their inbox, instead of their

Norton AntiSpam folder. There is an option in Norton that automatically adds

a sender to the blocked list if their message is filtered, is this turned on by

default? If so it seems like a lot of subscribers will be missing emails from us!

 

Thank you for the help!