Ionic http post doesn't send request

i have an error when i try to connect my api, i take http failer response for

my ts file:

import { HttpClient } from '@angular/common/http';
 import { Observable, throwError } from 'rxjs';
 import { catchError } from 'rxjs/operators';    

 const headers = {
  'Content-Type': 'application/json',
  'secretkey': 'xxx',
  'Access-Control-Allow-Origin' : '*',
  'Access-Control-Allow-Methods': 'POST, GET, OPTIONS, PUT',
  'Accept' : 'application/json',
  const options = {  headers:headers, withCredintials: true};

  try {'/',{},options)
     .subscribe(data => {
      this.users = data;
      alert("post catch error - "+error);

  } catch (error) {

the output is:

and then this output is shown:

my android manifest is:

<uses-permission android:name="android.permission.INTERNET" />
<application android:hardwareAccelerated="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:networkSecurityConfig="@xml/network_security_config" android:supportsRtl="true" android:usesCleartextTraffic="true">
    <activity android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|smallestScreenSize|screenLayout|uiMode" android:label="@string/activity_name" android:launchMode="singleTop" android:name="MainActivity" android:theme="@android:style/Theme.DeviceDefault.NoActionBar" android:windowSoftInputMode="adjustResize">
        <intent-filter android:label="@string/launcher_name">
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />

i use php slim framework for backend.
i add headers for cors problem.

but i can’t save my app.

please help me. it’s emergency

While you may need the secret key, you don’t need any of the rest of that junk in your custom headers, and things you don’t need shouldn’t be there, as they harm readability and often cause subtle problems.

/ also isn’t a valid URL.