CM5 sometimes response Internal server error when use /hosts API

cm_host_api.rb

# -*- coding: utf-8 -*-

require 'net/http'
require 'json'

def create_hosts
  res = Net::HTTP.start('10.211.55.100', 7180) do | http |
    req = Net::HTTP::Post.new("/api/v6/hosts")
    req.basic_auth('admin', 'admin')
    req.content_type = 'application/json'
    req.body = {
      items: [
        { hostname: 'cdh2', ipAddress: '10.211.55.102' }
      ]
    }.to_json
    http.request(req)
  end

  puts 'Hosts create'
  puts "Code: #{res.code}, Message: #{res.message}"
end

def hosts
  res = Net::HTTP.start('10.211.55.100', 7180) do | http |
    req = Net::HTTP::Get.new("/api/v6/hosts")
    req.basic_auth('admin', 'admin')
    http.request(req)
  end

  puts 'Hosts get'
  puts "Code: #{res.code}, Message: #{res.message}"
end

def delete_hosts
  res = Net::HTTP.start('10.211.55.100', 7180) do | http |
    req = Net::HTTP::Delete.new("/api/v6/hosts")
    req.basic_auth('admin', 'admin')
    http.request(req)
  end

  puts 'Hosts delete'
  puts "Code: #{res.code}, Message: #{res.message}"
end

10.times do
  puts '=' * 50
  create_hosts
  hosts
  delete_hosts
  sleep 1
end