Hi - I'm using 1708 Cloud with a test tenant. I was able to send emails to contacts through campaign execution before. However, it seems that after 1708 update, many emails(even the same ones) cannot be sent out successfully. If I go to contact's personal page, it is tracked as "outbound failed" under interactions. I saw from comments that I have to define whitelist in the campaign execution whitelist application. Is it true that I have to have everyone in my target group set up in the whitelist application? Is it just an issue with the test tenant?