Keycloak connection error using kcAdminClient and NestJS

I am working with keycloak and using this package https://www.npmjs.com/package/@keycloak/keycloak-admin-client to implement user edit functionality for every user. Backend is written on Nest.JS. This is app.service.ts code

import { Injectable } from '@nestjs/common';
import KcAdminClient from '@keycloak/keycloak-admin-client';

@Injectable()
export class AppService {
  private adminClient: KcAdminClient;

  constructor() {
    this.getAdminProperties().then(admin => {
      this.adminClient = admin;
    })
  }

  async getAdminProperties() {
    const kcAdminClient = new KcAdminClient();

    await kcAdminClient.auth({
      username: 'user',
      password: 'user',
      grantType: 'password',
      clientId: 'admin-cli',
      
    });

    kcAdminClient.setConfig({
      realmName: 'space-realm',
    });    

    return kcAdminClient;
  }

  updateUser(body: any, id: number): any {
    this.adminClient.users.update({ id: id.toString() }, body)
  }
}

And after this all code I am getting this annoying error:

(node:732) UnhandledPromiseRejectionWarning: Error: connect ECONNREFUSED 127.0.0.1:8080 at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1144:16)

(node:732) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag --unhandled-rejections=strict (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 2)

Maybe I am doing something wrong?