When you have your own domain it takes a couple more steps to start sending a campaign with verified and authenticated senders.
Go to Profile/Domain tab, click on Authenticate Domain.
Enter your domain name into the Domain name field, click Authenticate.
After a verification process finished the status of your domain will be set to Verified.
All the senders with email domain name firstname.lastname@example.org will be marked as Authenticated in the system.
The target audience will get marketing emails from email@example.com instead of firstname.lastname@example.org