VisualStudio运行正常，IIS部署后HttpClient无法连接求助

• 本地通过Visual Studio运行程序时，HttpClient可正常连接目标服务；部署至Windows Server 2012的IIS后，执行HttpClient.SendAsync时无限等待，无法解析目标域名https://app.xxxxxxx.com/。
• 服务器上Chrome浏览器可正常打开该目标页面，已尝试修改lmhost文件但无效，不清楚需在IIS还是Windows Server 2012中配置权限。

var client = new HttpClient();
var request = new HttpRequestMessage(HttpMethod.Post, "https://app.xxxxxxx.com/");
request.Headers.Add("Accept", "application/json");
request.Headers.Add("Authorization", "Bearer ...........");

string contentText = $@"{{""app_id"":""{_vInfo._id}"",""app_secret"":""{_vInfo._secret}""}}";

using (HttpContent content = new StringContent(contentText, null, "application/json"))
{
    request.Content = content;
    var response = await client.SendAsync(request);  //<<<---------- 此处无限等待
    response.EnsureSuccessStatusCode();
    string _result = await response.Content.ReadAsStringAsync();
}

Event code: 3001 
Event message: The request has been aborted. 
Event time: 15.11.2024 12:47:16 
Event time (UTC): 15.11.2024 09:47:16 
Event ID: 4d45d21891154f469c4ca24420c37d85 
Event sequence: 4513 
Event occurrence: 1 
Event detail code: 0 

Application information: 
    Application domain: /LM/W3SVC/1/ROOT-8-133761375015957277 
    Trust level: Full 
    Application Virtual Path: / 
    Application Path: C:\inetpub\wwwroot\MyWeb\ 
    Machine name: WIN22 

Process information: 
    Process ID: 7576 
    Process name: w3wp.exe 
    Account name: NT AUTHORITY\SYSTEM 

Exception information: 
    Exception type: HttpException 
    Exception message: Request timed out.

Request information: 
    Request URL: https://myweb.com:443/ConnectSvc 
    Request path: /ConnectSvc 
    User host address: xxx.xxx.xxx.xxx 
    User:  
    Is authenticated: False 
    Authentication Type:  
    Thread account name: NT AUTHORITY\SYSTEM 

Thread information: 
    Thread ID: 66 
    Thread account name: NT AUTHORITY\SYSTEM 
    Is impersonating: False 
    Stack trace: 

Custom event details: 

内容的提问来源于stack exchange，提问作者VolkanCetinkaya