The index events-training_stats_scalar-d1bd92a3b039400cbafc60a7a5b1e52b status is red. Meaning that the data for this index got corrupted. Since there are no replicas the only feasible option would be to delete this index. All the training scalars events for the old taskd would be lost then. But the newly created tasks should start working fine.
curl -XDELETE