There are several reasons members do not receive emails.
They clicked the unsubscribe link.
2. One of your team member's unsubscribed them (by mistake maybe?)
3. Email address was reported as an invalid email address.
4. Your emails were marked as "Spam."
RainMaker has a report to let you know who is not receiving your emails.
Go to: Marketing > Logs > Email
This report will show you if they have a bad email address on file, unsubscribed, or marked your email as spam.
https://addmembers.com/RainMaker/MessageCenter_Email_Logs.aspx
5. Email inbox was "full" at time we tried to deliver.
6. Your contact's email server was too busy at the time we tried to deliver.
Our policy: Only contacts you know or have asked you to send them email can be used. No mass email marketing pieces to contacts that did not specifically ask to be contacted by you.
We all care about our email being delivered to our contacts reliably, right? For every message marked as SPAM by our contacts, our SPAM score goes up and up. The higher the SPAM score... the lower our delivery rate will be. Some mail services will automatically start blocking you before it ever gets to the intended person, in addition, your contacts also have SPAM filters that will automatically mark it as SPAM and it will go straight to their "SPAM FOLDER."
Want more info on how to send better email?
The US Government has a website that's easy to understand it also explains the CAN SPAM act, a law in the US: http://business.ftc.gov/documents/bus61-can-spam-act-compliance-guide-business
Here is a link to an article with helpful info on better deliverability. http://www.masternewmedia.org/news/2008/05/24/spam_checking_tools_and_tips.htm
Tips and Tricks to Stay out of the SPAM Folder:
https://sendgrid.com/blog/top-10-tips-and-tricks-to-stay-out-of-the-spam-folder-2-0/