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Airflow: Dependencies not met for <TaskInstance>, dependency '...' FAILED
Dependencies not met for <TaskInstance: sales.load_orders manual__2026-10-22 [queued]>, dependency 'Trigger Rule' FAILED: Task's trigger rule 'all_success' requires all upstream tasks to have succeeded, but found 1 non-success(es).Airflow checked whether a task instance may start and one of its scheduling dependencies failed. This is an informational log line: the text after FAILED explains which rule blocked the task, such as upstream states, pool slots or concurrency limits.
Common causes
- Upstream tasks have not finished in a state the trigger rule accepts, for example an upstream failure with the default all_success rule.How to confirm: The reason mentions the trigger rule and counts of upstream states.
- A pool or concurrency limit is full (pool slots, max_active_tasks, max_active_tis_per_dag).How to confirm: The dependency name is 'Pool Slots Available' or a concurrency check.
- The task was cleared or retried and is waiting for its retry delay.How to confirm: The dependency mentions the retry period.
How to fix it
Read the reason after FAILED and fix that rule: change the trigger_rule, free or enlarge the pool, or raise the concurrency limit.
In the UI, the task instance details page lists the same dependency checks and which one is blocking.
Where the message comes from
taskinstance.pyinapache/airflowat3.3.2- Message checked in Airflow 3.3.2
Message template in the source: Dependencies not met for %s, dependency '%s' FAILED: %s