Failed Email Delivery
I am a beginner in Adobe Campaign and using sandbox version given by my company. I created a simple campaign with a list containing just one email and one email delivery attached to it. I disabled the approval workflows and initiated the delivery but every time the delivery fails with message
"Message queued (session with SMTP Server: #HOSTNAME#."
and it says email is unreachable which is in fact a valid email-id.
Kindly help me in debugging or guide me to create at least a single email delivery.