Ionic push notification error curl request

When I send a curl request* to send a notication like in documentation:

I get the response 415 UNSUPPORTED MEDIA TYPE.
IF I send the same curl with a GET request (instead of a POST) the response is OK.
But I dont see a notification on my device.

It seems that the POST isnt’ supported. So what is the correct CURL request?

curl request
curl -X POST -H “Authorization: Bearer API_TOKEN” -d ‘{
“tokens”: [“DEV_DEVICE_TOKEN”],
“profile”: “fake_push_profile”,
“notification”: {
“message”: “Hello World!”
}’ “

solved it. had to set the Content-Type: application/json.