How to SendRequest with correct body by using wininet in mql4 - wininet

Question

I have dummy web service with URL: http://47.91.231.122:5002/token which return data in JSON I want to call this service using WINInet APi in mql.Can anybody help me how to use contruct "HttpSendRequest" method to add header and data to call this service?
enter image description here
Get the access token from the server by enter all the required data in the call body.
URL: http://47.91.231.122:5002/token
username:admin#admin.com
password:111111
grant_type:password
Below is my code.
Please guide me how to do it correctly. Thanks
#import "Wininet.dll"
int InternetOpenW(string name, int config, string, string, int);
int InternetConnectW(int hopen, string, int, string, string, int, int, int);
int HttpRequestW(int hconnect, string, string, int, string, int, string, int);
int InternetOpenUrlW(int, string, string, int, int, int);
bool InternetReadFile(int, uchar &sBuffer[], int, int& OneInt);
bool InternetCloseHandle(int); [enter image description here][1]
int HttpOpenRequestA(int, string, string, string, string, string& AcceptTypes[], int, int);
bool HttpSendRequestA(int, string, int, string, int);
#import
#import "kernel32.dll"
int GetLastError(void);
#import
is the header and body data correct?
int init()
{
string headers = "Content-Type: application/x-www-form-urlencoded\r\n";
string data = "{\"username\":\"admin#admin.com\",\"password\":\"111111\",\"grant_type\":\"password\"}";
string acceptTypes[1] = {"*/*"};
int httpconnect=0;
int HttpRequest =0;
int httpopen = Wininet::InternetOpenW("Phoenix_API", 0, " "," ",0 );
int e=kernel32::GetLastError();
printf("HttpOpen=0 = "+httpopen+", "+e);
if (e==0)
{
Base on the picture, am i code it correct to connect it?
httpconnect = Wininet::InternetConnectW(httpopen, "47.91.231.122", 5002, NULL, NULL, INTERNET_SERVICE_HTTP, 0, 1);
printf("httpconnect=0 = "+httpconnect+", "+e);
e=kernel32::GetLastError();
if (e==0)
{
HttpRequest = HttpOpenRequestA(httpconnect, "POST", "/token", NULL, NULL, acceptTypes, 0, 1);
e=kernel32::GetLastError();
printf("HttpRequest = "+HttpRequest+", "+e);
if (e==0)
{
bool A = HttpSendRequestA(HttpRequest, headers, StringLen(headers), "", 0);
e=kernel32::GetLastError();
printf("A = "+A+", "+e);
i get a dummy message DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
//--- Define buffers
uchar ch[512]={0,0,0,0};
string temp="";
//--- Retrieve data from file
int cnt=0;
while(Wininet::InternetReadFile(HttpRequest,ch,512,cnt))
{
if(cnt<=0) break;
temp=temp+CharArrayToString(ch,0,cnt);
printf(temp);
}
MessageBox(temp, "HTTP READ:", 0x00000030);
}
}
}
//--- Close connection
if (HttpRequest > 0) InternetCloseHandle(HttpRequest);
if (httpconnect > 0) InternetCloseHandle(httpconnect);
if (httpopen > 0) InternetCloseHandle(httpopen);
}