收到了关于DynamoDB tableName的验证错误，但无法确定具体错误

【以下的问题经过翻译处理】 具体的错误如下所示：

"code": "INTERNAL_SERVER_ERROR",
        "exception": {
          "message": "1 validation error detected: Value '[object Object]' at 'tableName' failed to satisfy constraint: Member must satisfy regular expression pattern: [a-zA-Z0-9_.-]+",
          "code": "ValidationException",
          "time": "2019-07-25T05:43:18.119Z",
          "requestId": "xxx",
          "statusCode": 400,
          "retryable": false,
          "retryDelay": 42.11544763698385,
          "stacktrace": [ ...

我猜问题可能是表的名称，但是表名已经命名正确。下面是实现的代码：

const putItem = (tableName, newItem) =>
  new Promise((resolve, reject) => {
    const params = {
      TableName: tableName,
      Item: newItem,
    };
    docClient.put(params, (err, data) => {
      if (err) {
        return reject(err);
      }
      return resolve(newItem);
    });
  });

由于我在使用GraphQL，下面是resolver：

const resolvers = {
  Mutation: {
    createUser: (root, { params }) => {
      const tableName = 'Users';
      return bcrypt
        .hash(params.password, 12)
        .then(hashedPassword => {
          const newUser = {
            _id: uuidv5(params.email, nameSpaces.usersTable),
            email: params.email,
            password: hashedPassword,
          };
          return dynamoConnection.putItem(newUser, tableName);
        })
        .then(result => ({ ...result, password: null }))
        .catch(err => {
          throw err;
        });
    },
  },
};

为了调试这个错误，我应该怎么做？