Angular (failed)net::ERR_CONNECTION_TIMED_OUT

Question

I have one weird problem. I have one angular web application in x server with https with trusted certificate. And I have one api in another y server which doesn't have trusted certificate. y server is only internal . It means only x server can reach y. I publised angular app and trying to send request to api but giving me

(failed)net::ERR_CONNECTION_TIMED_OUT

error in network. So I can't figure out what the problem is.

I tried to understand if problem is api related and tried below examples

1. I created one api in x server and send request to y server with this api and it works
2. I created simple html file in server and inside it tried to send request to api in y server and it works

so only Angular app doesn't send this request.

Below is my http service

import { Injectable } from '@angular/core';
import { HttpClient, HttpErrorResponse, HttpHeaders } from '@angular/common/http';
import { Observable, throwError } from 'rxjs';
import { environment } from 'src/environments/environment';

@Injectable({
  providedIn: 'root',
})
export class HttpService {
  constructor(private http: HttpClient) {}

  Get(url: string): Observable<any> {
    return this.http.get(environment.apiUrl+ url).pipe();
  }
  Post(url: string, object: any): Observable<any> {
    return this.http.post(environment.apiUrl+url, object).pipe();
  }
  Put(url: string, object: any): Observable<any> {
    return this.http.put(environment.apiUrl+url, object).pipe();
  }
  Delete(url: string, object: any): Observable<any> {
    const options = {
      headers: new HttpHeaders({
          'Content-Type': 'application/json'
      }),
      body: object
  } 
    return this.http.delete(environment.apiUrl+url, options).pipe();
  }
}

and I send request using this service

    this._http.Post('Report/BatchCounts', this.filter).subscribe(
      (result) => {
        if (result.success) {
          this.batchData = result.data;
        }
        this._loader.stop();
      },
      (error) => {
        this._loader.stop();
      }
    );

what can be the problem ? What can be my problem?

Thanks in advance