Campaigns will not be sent to a client if they:

• Previously unsubscribed from your campaigns.
• Have not opted-into marketing campaigns and you require clients to be opted-in.
• Are 'blocked'. This means we previously tried to send emails to this client and they bounced. For more details on why emails bounce, click here.
• The client does not have an email address associated.

To filter out blocked and unsubscribed clients in your client list,

1. Navigate to Clients.
2. The client filters are on the right-hand side. Click the Advanced option to expand advanced filters. 
3. Select the Unsubscribed or Email Blocked (or both) filters to filter out those clients. You can use Select > All > Add Tags from the top of the page to add a tag to those clients or perform other bulk actions.