DAG read access alone may not be enough. In Airflow 3.1.8, the graph data endpoint also checks DAG dependencies and task-instance access. FAB maps task-instance access to both DAG Runs and Task Instances.

Check that the affected user's role has can_read on:

• DAG:<dag_id> (or DAGs for access to all DAGs)
• DAG Dependencies
• DAG Runs
• Task Instances

As that user, open DevTools → Network, reload the DAG page, and check the structure_data request. A 403 there would support missing permissions as the cause. Add any missing permissions to the role, sign in again, and retry the same DAG.

If it still fails, share the installed FAB provider version, the failing request URL/status, and the role's relevant permissions. If no request fails, mention that too.