Not able to get http response from a third party API when code deployed to azure function app, in debug mode its working fine – Asp.net

I have created an azure http trigger (also tried with timer trigger) function and it is calling an third party API with necessary params as content header. Locally in VS Code (debug mode), it’s working fine. I am getting desired response (getting token if we call token end point as well as proper response if we call another end point by passing token). Even with postman I am getting correct response.

But when I deployed this function to azure function app, it’s not getting response from both endpoint. (either from token one or if I pass hardcoded token copied from postman to second endpoint).

In logs, I can see function being called and when I am logging response I am getting a large html text(don’t know what is that)
Is it possible that third party API is blocking or restricting calls from azure function(though it’s working locally or with postman if we pass proper values)
Tried everything but can’ find out the exact issue. I have verified I am passing correct values as grant_type, client_Id, client_secret, username, password, scope)

Have pasted below sample piece of code:

private async Task<Token> GetToken()
  {
    try{
     HttpContent content = new FormUrlEncodedContent(new Dictionary<string, string>
    {
        {"grant_type", Environment.GetEnvironmentVariable("test-grant-type")},
        {"username", Environment.GetEnvironmentVariable("test-username")},
        {"password", Environment.GetEnvironmentVariable("test-password")},
        {"client_id", Environment.GetEnvironmentVariable("test-client-id")},
        {"client_secret", Environment.GetEnvironmentVariable("test-client-secret")},
        {"scope", Environment.GetEnvironmentVariable("test-scope")}
    });
    
    HttpClient client = new HttpClient();
    
    string tokenEndPoint = Environment.GetEnvironmentVariable("test-tokenApiEndPoint");
    
    //calling API
    HttpResponseMessage messageResult = await client.PostAsync(tokenEndPoint, content);        

                    
    _logger.LogInformation($"Log Info:  GetToken method: httpResponseMsg: {messageResult}");
    
    string apiResponse = messageResult.Content.ReadAsStringAsync().Result;

    _logger.LogInformation($"Log Info:  GetToken method: apiResponse: {apiResponse}");
    
    Token resTokenModel = JsonConvert.DeserializeObject<Token>(apiResponse);
    }
    catch (System.Exception ex)
    {
        _logger.LogError($"Exception : GetToken Method: Exception: {ex.Message}");
        throw new Exception(ex.Message);
    }
return resTokenModel;
}

Log html response sample (it’s not complete as it is very large), Log1:

2022-06-29T08:30:05.490 [Information] Log Info:  GetToken method: httpResponseMsg: StatusCode: 200, ReasonPhrase: 'OK', Version: 1.1, Content: System.Net.Http.HttpConnectionResponseContent, Headers:{Cache-Control: no-store, no-cachePragma: no-cacheStrict-Transport-Security: max-age=31536000; includeSubDomainsX-Content-Type-Options: nosniffX-Frame-Options: DENYLink: <https://aadcdn.msauth.net>; rel=preconnect; crossoriginLink: <https://aadcdn.msauth.net>; rel=dns-prefetchLink: <https://aadcdn.msftauth.net>; rel=dns-prefetchX-DNS-Prefetch-Control: onP3P: CP="DSP CUR OTPi IND OTRi ONL FIN"x-ms-request-id: 18670f19-3bec-4556-9b66-2c3760855300x-ms-ests-server: 2.1.13006.6 - WEULR1 ProdSlicesX-XSS-Protection: 0Set-Cookie: buid=0.AQIANaKxxxx_PBbRZsxxxx_PzErkPdDcCAdAA.xxxx--DLA3VO7QrddgJg7WevrDRjJU0T4KWPoylW2bC-ExpJHweIFWSInAdxjVwFITAQNF_FKbJPKHxxxxxp9ivEPYDacemz4wUo_sc04zyJbXjfz-2bVvxUz-AgAA; expires=Thu, 28-Jul-2022 08:30:05 GMT; path=/; secure; HttpOnly; SameSite=NoneSet-Cookie: fpc=AsZ-7OJNXMJAsZa7WVUJsyzxSauWAQAAAAyzTNoOAAAA; expires=Thu, 29-Jul-2022 08:30:05 GMT; path=/; secure; HttpOnly; SameSite=NoneSet-Cookie: esctx=AQABAAAAAAD--DLA3VO7QrddgJg7WevrvlcjjHs6JSFKoM9RHgIe1sGicQYOARxxxxwtTCtFHUZ7DawxrkQC4x3uxxkXSFkTTUgthZA1MEqk-Pmv2mzfkL9xBHg1V-LSzxeaWxtB38SA--OJKRBbdBVRR0D80RGqwGWTn5bm4XeaaWFCt5SYYet_q1fuHwxUMe7OXIuQgAA; domain=.login.microsoftonline.com; path=/; secure; HttpOnly; SameSite=NoneSet-Cookie: x-ms-gateway-slice=estsfd; path=/; secure; httponlySet-Cookie: stsservicecookie=estsfd; path=/; secure; httponlyDate: Tue, 28 Jun 2022 08:30:04 GMTContent-Type: text/html; charset=utf-8Expires: -1Content-Length: 195652}

from below html, I can only understand "Sign in to your account" but where to sign, Log2:

2022-06-28T08:30:05.492 [Information] Log Info: Synergi Repo: GetToken method: apiResponse:<!-- Copyright (C) Microsoft Corporation. All rights reserved. --><!DOCTYPE html><html dir="ltr" class="" lang="en"><head><title>Sign in to your account</title><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=2.0, user-scalable=yes"><meta http-equiv="Pragma" content="no-cache"><meta http-equiv="Expires" content="-1"><link rel="preconnect" href="https://aadcdn.msauth.net" crossorigin><meta http-equiv="x-dns-prefetch-control" content="on"><link rel="dns-prefetch" href="//aadcdn.msauth.net"><link rel="dns-prefetch" href="//aadcdn.msftauth.net"><meta name="PageID" content="ConvergedSignIn" /><meta name="SiteID" content="" /><meta name="ReqLC" content="1033" /><meta name="LocLC" content="en-US" /><meta name="referrer" content="origin" /><meta name="format-detection" content="telephone=no" /><noscript><meta http-equiv="Refresh" content="0; URL=https://login.microsoftonline.com/jsdisabled" /></noscript><meta name="robots" content="none" /><script type="text/javascript">//<![CDATA[$Config={"fShowPersistentCookiesWarning":false,"urlMsaSignUp":"https://login.live.com/oauth20_authorize.srf?response_type=codeu0026client_id=5xxx2-085c-xxxx-bf88-xxxxx8u0026scope=openid+profile+email+offline_accessu0026response_mode=form_postu0026redirect_uri=https%3a%2f%2flogin.microsoftonline.com%2fcommon%2ffederation%2foauth2msau0026state=rQQIxxxxxxFM4lbVARUISEBAuDmwnlYp99Z8dGDEFtIWogJQGEUCQ4n-_SE845sZ2UgBj5GZkYChISYycEC3QBJIREp0wIMSPBABJbO-KUFYnlLe99f-87Wxxxxkk1A8g9i0b-pawoLCQ6buGcLDlxEf2H_549xxxxvH95ugLnroRzxCot6m-DEWpr2E0_Xk7HicVcOaIUPhlJF8XSvvwZgAsAPADbzJYdaFAufQMQtA2LmBpASIaAgriAkEAjR6tf8fLM2TNfM6YhieZtvFB7ka_3-ahzdGrdTmnLvjlZXIxrK4FJ0k6sWT-Ox5qlhGJa1enI-iYRPNU_QMOFlrRnLrlQ0bNH1y3Goedpfux2982_DHb2puAy4SmU67ugsUoqztKOnUxxxxx4PMkZs0Sp1GIaYZy_EJnGgbwgTWowz5mAfE-FmyDZPEhmpPYiDGEKE2dCx7QzCmAt9GhjQtlwR2Dwj84V2d2FJBU2xl3mVxrS38LJQsijF1LQI9G1uQlwNCHSRS6AjmDBIpuX6xnahGPW5ksGXApjMgN0Z8Hw26_H4fPfYz1NXlp6IsnPjXju3PasnA0MuXsNdtFLt9thyO0zZsoqvxiuN9bONOg4vLEbDxsUzdnVQO4089KgIfhfBw325rbn_1P7iAHh3MLd7aOfbqzf3nz7-de4P0u0026estsfed=1u0026uaid=71c115c676664cc9bad0639fd6e7c4bfu0026signup=1u0026lw=1u0026fl=easi2u0026fci=7e7dac8e-5abd-4b36-b3f3-f312b90f7437","urlMsaLogout":"https://login.live.com/logout.srf?iframed_by=https%3a%2f%2flogin.microsoftonline.com","urlOtherIdpForget":"https://login.live.com/forgetme.srf?iframed_by=https%3a%2f%2flogin.microsoftonline.com","showCantAccessAccountLink":true,"urlGitHubFed":"https://login.live.com/oauth20_authorize.srf?response_type=codeu0026client_id=xxx-085c-xx-bf88-xxxu0026scope=openid+profile+email+offline_accessu0026response_mode=form_postu0026redirect_uri=https%3a%2f%2flogin.microsoftonline.com%2fcommon%2ffederation%2foauth2msau0026state=rQQIAxxxVE9bNNAxxxISEBAuDmwnlYp99Z8dGDEFtIWogJQGEUCQ4n-_SE845sZ2UgBj5GZkYChISYycEC3QBJIREp0wIMSPBABJbO-KUFYnlLe99f-87WUAV5JUc7gSUVTkxxxx-pawoLCQ6buGcLDlxEf2H_549P1AjD41tibs2efvH95ugLnroRzxCot6m-DEWpr2E0_Xk7HicVcOaIUPhlJF8XSvvxxxbzJYdaFAxxxxxiAkEAjR6tf8fLM2TNfM6YhieZtvFB7ka_3-ahzdGrdTmnLvxxxrK4FJ0k6sWT-Ox5qlhGJa1enI-iYRPNU_QMOFlrRnLrlQ0bNH1y3Goedpfux2982_DHb2puAy4SmU67ugsUoqztKOnUymtrLWyW56kmRshQ14PMkZs0Sp1GIaYZy_EJnGgbwgTWowz5mAfE-FmyDZPEhmpPYiDGEKE2dCx7QzCmAt9GhjQtlwR2xxxxd2FJBU2xl3mVxrS38LJQsijF1LQI9G1uQlwNCHSRS6AjmDBIpxxxxsGXApjMxxx26_H4fPfYz1NXlp6IsnPjXju3PasnA0MuXsNdxxxvxiuN9bONOg4vLEbDxsUzdnVQO4089KgIfhfBw325rbn_1P7iAHh3MLd7aOfbqzf3nz7-de4P0u0026estsfed=1u0026uaid=71c115c676664cc9bad0639fd6e7c4bfu0026fci=7e7dxxxx-b3f3-f312b90f7437u0026idp_hint=github.com","fShowSignInWithGitHubOnlyOnCredPicker":true,"fEnableShowResendCode":true,"iShowResendCodeDelay":90000,"sSMSCtryPhoneData":"AF~Afghanistan~93!!!AX~Åland Islands~358!!!AL~Albania~355!!!Islands~358!!!AL~Albania~355!!!
---------
-- and so here is large html content as above ---

————————————————————————————————–
Exception log:
This is because in code we are parsing response (so below issue is because it tried to parse response html) – so this does not seems to be useful

2022-06-29T15:18:14.657 [Error] Exception : GetToken Method: Exception: Unexpected character encountered while parsing value: '<'. Path '', line 0, position 0.
2022-06-29T15:18:14.710 [Error] Exception :  Method: Exception: One or more errors occurred. (Unexpected character encountered while parsing value: '<'. Path '', line 0, position 0.)

If anyone has faced similar issue or can give an idea what can be the cause, though it’s hard to find just looking in to code

Thanks