Zoho sent mail statistics "#'s emails blocked cant be sent"

Zoho sent mail statistics "#'s emails blocked cant be sent"

I originally sent tan email to 41 people and only 2 were successful and got this notifications in the photo. I tried it again with one of the emails that was unsuccessful and this is the message i got (in the photo).

What I would like to know is...
1. I would like to be able to see the contacts that have been marked blocked or invalid
2. I would like to know why they were blocked