How can I properly use "Improve search results with search tuning" method

Hello, I was trying the method in the link below as a way to improve the search results for Vertex AI Search & Conversation.

Improve search results with search tuning | Vertex AI Search and Conversation | Google Cloud

I tried to train a custom model using the curl command using sample data, but no matter how many times I try, I get the following Internal Server error.

The status changes as shown below after the first curl post, and eventually an error occurs.

in-progress

training

evaluating

training

evaluating

In particular, I can’t check the error log, so I’m having trouble identifying the cause.
Could someone please help?

{
“code”: 13,
“message”: “Internal error encountered. Please try again. If the issue persists, please contact our support team.”
}

The following three types of training data were used.

  1. corpus.jsonl
    2.query.jsonl
  2. training-label.tsx