Testing your email campaigns is a very important part of the process of creating your Enudge emails.
If you find that the Email Test option is missing from the Content and Test screen in your draft email campaign, that's because you have attached more than 500 contacts to your campaign, and we didn't want you to have to search through that many contacts to find the right email address!
Simple solution: remove the contacts from your campaign, attach just the contacts you would like to test, and then you will be able to send your test message/s. Once you are ready to send your campaign, attach the appropriate set of contacts, and send as per normal.
Alternatively, if you are trying to send a test message to an email address which you have attached to your draft campaign, and you receive an error upon sending, check that:
the email address hasn't unsubscribed - check this by editing the contact, and
the email address hasn't bounced - check this via the Bounced Contacts report - see the 'Reports' drop down in the Contacts screen.