Sending data from GSM module to Thingspeak using TCP | ThingSpeak API | Forum

hi all,

I am trying to send data from gsm module to my channel on thingspeak. But data is not getting send.
For tcp connection I have given domain name: api.thingspeak.com and port no.: 443 (since https)

I am Able to make connection but while sending data to to channel it fails.
send body consits of update?api_key=SRQDIRQE1UJ1HKHE&field3=98.1212

I think above is right format but still having problem while sending data from GSM module. I am using quectel M66 gsm module.
Response consists IPD288:HTTP/1.1 400 Bad Request

Any help will be appreciated!!