Campaign workflow won't run
Symptom
Campaign workflow is stuck in the 'Start as soon as possible' state.

Cause
Campaign Jobs technical workflow has failed:

Fix
Restart the Campaign jobs workflow.
Preventative
Administrators can click on the Monitoring on the Home page and the Monitoring instance Dashboard shows all workflows in need of assistance. Even better, one or more Administrators should add themselves to the Workflow supervisors Operator group and they will receive notification when this workflow is suspended (fails).
