This looks like the email was pre blocked as it contained what looked like spam. 

You should look at re-wording the email (duplicate it first) then re-word it – take out any spammy words i.e. Free, Sale, discounts etc as well as using symbols i.e.  !!!, ???, %, * and even remove any words in CAPITALS and then you should be able to send it out again and it should be OK.

Internet Service Provider (ISP) blocking your emails

In the case of bounces to a large number of email addresses at the same domain - it may indicate that your emails are being blocked by the Internet Service Providers (ISPs) receiving server, such as email to Yahoo, Hotmail or Gmail accounts. 


ISPs and other mail systems check incoming mail from each source and can see if you are sending to a lot of addresses that are bouncing. 


If they detect that you are then they will start rejecting your campaigns on the assumption your list is made up of automatically generated or purchased emails. 


In other words, they may be blocking you on the assumption that you are a spammer.  Our advice would be to contact the ISP that handles this mail to ask them to unblock you as a sender of email. 


You may need to set up SPF/DKIM records in order to make sure your email is received, if they ask for this please our Support Desk so that we can provide you with these details from our email platform.