Data not getting posted to my api

Hello everybody!
so far i have been posting my data to api.thingspeak and went cool...now i wanted to post some data to another api....i just cant....heres the link to which i want to post my data to....i got this link from webpage's
"developer's options"

HTTP/1.1 304 Not Modified
Server: Cowboy
Content-Length: 0
Connection: keep-alive
X-Powered-By: Express
Access-Control-Allow-Origin: *
Etag: W/"2-nOO9QiTIwXgNtWtBJezz8kv3SLc"
Date: Wed, 02 Jan 2019 09:46:56 GMT
Via: 1.1 vegur

and heres how i did to thingspeaks'

client.print("POST /update HTTP/1.1\n");
       client.print("Host: api.thingspeak.com\n");
       client.print("Connection: close\n");
       client.print("X-THINGSPEAKAPIKEY: " + API_KEY + "\n");
       client.print("Content-Type: application/x-www-form-urlencoded\n");
       client.print("Content-Length: ");
       client.print(postStr.length());
       client.print("\n\n");
       client.print(postStr);
       delay(1000);

and heres how i merged 'em and they didnt work

client.print("POST /HTTP/1.1 200 OK\n");
       client.print("Server: Cowboy\n");
       client.print("Connection: keep-alive\n");
       client.print("X-Powered-By: Express\n");
       client.print("Access-Control-Allow-Origin: *\n");
       client.print("Content-Length: 2");
//       client.print(postStr.length());
//       client.print("\n\n");
       client.print(postStr);

also i expected to use http.prient,but that works only for arduino yun....it would have been easier with that function if it was cool with node mcu.....could someone please suggest me with a solution
thanks in advance

POST /HTTP/1.1 200 OK\n ???

Thanks juraj
....what do you mean??????????

sabishaw:
Thanks juraj
....what do you mean??????????

HTTP is a protocol. you can't send random copy paste. You mixed request and response line type

RFC 2616 page 35

The Request-Line begins with a method token, followed by the
Request-URI and the protocol version, and ending with CRLF. The
elements are separated by SP characters.

Bro...i just cant quite understand.....and nothing in the link you gave me....for i ma f****ing newbie.....could you please elaborate and suggest the changes....
thanks