A6 GSM module - problem with posting JSON

Hello. I am trying to post JSON object to my heroku web app which, among others, has a function to parse JSON and returns some sort of an answer. Posting normal text data works fine, GET request works fine. I am just having trouble posting JSON data.

Here are the commands I use:

at+cipstart="TCP","nemanjalexus.herokuapp.com",80 at+cipsend

POST /processjson HTTP/1.1 Host: nemanjalexus.herokuapp.com Content-Type: application/json Content-Length: 78

{"name":"jimmy","location":"sweden","randomlist":["one","six","three","four"]}

CTRL-Z (character that finishes the entry)

I receive the following answer from the server:

+CIPRCV:134,HTTP/1.1 505 HTTP Version Not Supported Connection: close Server: Cowboy Date: Sun, 29 Mar 2020 09:50:26 GMT Content-Length: 0

I think that my problem is caused by HTTP headers I use, but I can't figure it out.

Maybe someone else has some ideas.

You failed to post your code so I'm force to wildly guess: It looks like you have an empty line at the beginning of your post. The server will interpret that as the end of the header, resulting in an unknown HTTP version recognized.