Ground Truth Label Jobs: "cannot read properties of undefined (reading 'split')"

I was using SageMaker Ground Truth in Amazon Web Services to create a crowdsourcing data labeling job. When I finished all the procedures, the system told me, "cannot read properties of undefined (reading 'split')." I tried again and again, but it still did not work. What did it mean? And how can I solve the problem? I could launch the task with my private worker team employed. But it would fail if I chose to use the MTurk workforce.