Thanks for joining us in the Community! We certainly understand that each email address you have is valuable. Blocked bounces typically mean the receiving domain blocked the message (typically for either reputation or content). If you've been able successfully send to them in the past, it may be a certain piece of content on the newsletter that triggered the receiving server to block it. Other bounces are non-standard bounces that we were unable to categorize. We have a delivery team that would be happy to help review the content in your newsletter to check for anything potentially problematic. For hours and best contact phone numbers please click here.