A flow gets stuck in waiting state. There is no error reported, but the last action says not run.
It could be a design problem. Check if the first action that says not-run depends on the value for an earlier action. For example a look-up record might depends on a condition: sys_id=18->Task Record->Sys ID. If step 18 was never executed, it gets stuck at this point.
You need to make sure an action references a valid older action.