This article explains why orchestration plan items in Salesforce Communications Cloud transition to the Ready state but don't execute, and how to resolve it. When an orchestration item of type Auto Task or Callout reaches the Ready state, the Vlocity CMT package publishes an OrchestrationEvent platform event that is consumed by the OrchestrationEventHandler Queueable class to advance the item to Running and Completed. If the Queueable job fails in the background with common errors include "Apex heap size too large","Apex CPU time limit exceeded" or any other exception — the item remains Ready and the plan stalls. Some times in sandboxes cloned from another sandbox or production, the OrchestrationEvent platform's event subscription may not fire at all.
PFB the details of the Possible RCA of this issue:-
Cause 1: Failed OrchestrationEventHandler Queueable jobs
Cause 2: OrchestrationEvent platform event trigger not firing in cloned sandboxes
This cause applies when the sandbox was refreshed or cloned from another sandbox or production org and orchestration items have never advanced from Ready since the clone.
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