Cann't connect SQL server with xamarin form using http request web api

<stacklayout padding="5">        
        <listview x:name="MainListBox">            
            <listview.itemtemplate>
                <datatemplate>
                    <viewcell>
                        <stacklayout>

public MainPage()
{
    InitializeComponent();
    _Load();
}
private async void _Load()
{
    var httpclient = new HttpClient();
    var response = await httpclient.GetStringAsync("https://localhost:22348/api/customer");
    var login = JsonConvert.DeserializeObject<list<customer>>(response);
    MainListBox.ItemsSource = login;
}

System.Net.WebException
  Message=failed to connect to localhost/127.0.0.1 (port 22348) after 86400000ms: isConnected failed: ECONNREFUSED (Connection refused)

System.Net.Http.HttpRequestException
  HResult=0x80072EFD
  Message=An error occurred while sending the request.
  Source=System.Net.Http
  StackTrace:
   at System.Net.Http.HttpClientHandler.<sendasync>d__111.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Net.Http.HttpClient.<finishsendasyncunbuffered>d__59.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Net.Http.HttpClient.<getstringasynccore>d__27.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at App5_temp2.MainPage.<login>d__1.MoveNext() in C:\Users\HRS7_PC\source\repos\App5_temp2\App5_temp2\App5_temp2\MainPage.xaml.cs:line 28

Inner Exception 1:
COMException: The text associated with this error code could not be found.

A connection with the server could not be established