Make sure you have a clean set up. And no Alpha running at the same time. Bulk just need Zero group. If you are using K8s, you have to find a way to delay the startup of Alphas.
This error could be two things. Zero is having a problem(config or some files from old instances in the path that wasn’t correctly cleaned). Or The cluster has Alpha running.
A possible problem could be in the dataset. If you use the --new_uids flag it might solve it. Pay attention. Even if it does, you need to make sure you started a cluster from scratch.
Share the command used to run the bulkloader.