The most likely reason is that you haven't approved your email to send.
Head to the timeline <https://hq.ampjar.com/emails/dash/overview> and if your campaign has the tag Ready then it is good to go. Otherwise you'll need to go into your campaign and click approve to send.
If on the dashboard your campaign is tagged Not Sent then hit rescue to pick a new send time, if it says Approval Required then you must go and approve your campaign. If it say Upcoming then hit Create campaign now and we'll build your campaign for you.