Gets duplicated mapping key error using openapi 3.0 - yaml

Question

I am trying to define my APIs using openapi version 3.0.0. I've generated following YAML file:
openapi: 3.0.0
info:
title: My YAML
description: My YAML
version: 1.0.0
servers:
- url: http://my.server.url
paths:
/v1/service/uri:
post:
summary: Getting some information.
parameters:
- name: Content-Type
in: header
description: Content type of request body.
required: true
style: simple
explode: false
schema:
type: string
- name: Host
in: header
description: Originate host which returns the response.
required: false
style: simple
explode: false
schema:
type: string
requestBody:
content:
application/json:
schema:
$ref: '#/components/schemas/MyPostRequest'
example:
my_name: "zizi"
my_age: 29
required: true
responses:
200:
description: OK
content:
application/json:
schema:
$ref: '#/components/schemas/MyPostResponse'
components:
schemas:
MyPostRequest:
type: object
properties:
my_name:
type: string
my_age:
type: integer
format: int32
MyPostResponse:
type: object
properties:
status:
type: integer
format: int32
When I copy/paste these lines into Swagger Editor, it gives me duplicated mapping key error on line 19; it is for section description of parameter Content-Type.
I have studied openapi documentation, but I didn't see anything wrong with my YAML file.

Answer 1

I am not sure why you get that error, I tried to find out in which language Swagger is written, as there are several YAML parsers out there that are known to have problems, but couldn't easily determine that using google or wikipedia.
You don't have any duplicate keys in your file, but it is invalid (i.e. not valid YAML) because of the indentation of the key content (the second occurrence, the one under paths →
/v1/service/uri → post → responses → 200), that should be aligned with
description as that key cannot have a value node that is both a scalar (OK) as well as a mapping node content: ....