Check that all necessary approvals have been done for this delivery.
Check that the operationMgt and deliveryMgt technical workflows are running without any errors.
Check that the delivery is not using an affinity that has not been configured on the sending instance.
A delivery with a “pending” status means that the execution process is waiting on the availability of some resources.
If your email campaigns aren't being sent on the corresponding contact date and their status is Pending, the module that manages email sending (MTA) in Adobe Campaign may have not been started. Check this with your Adobe Campaign Administrator.