After cloning a pipeline you might notice that the cloned pipeline won't run. The error message seen:
Failed to trigger stage [Update] pipeline [PipeLine_Name]
Could not find matching agents to run job [Job_Name] of stage [Stage_Name].
In such a case please confirm if the agent (that was running this job in your previous pipeline) belongs to a particular environment.
By assigning an agent to an environment, it will be used to run only those jobs that belong to the pipelines of that environment. An agent can belong to more than one environment. By default a cloned pipeline is not part of the same environment as its parent.