Send message get 400404 Platform API Error

I send this curl request:

curl --location --request POST 'https://api-{{my app id}}{{my group channels}}/messages' \
--header 'Api-Token: {{my api token}}' \
--header 'Content-Type: application/json' \
--data-raw '{
    "message_type": "MESG",
    "user_id": "firman",
    "message": "test from frm"

and got this:

    "message": "Platform API Error",
    "code": 400404,
    "error": true

I can create channels and register user with my credentials but can’t send messages.

Hi @yusufmalikul ,

Welcome to Sendbird Community!

Could you DM me your application ID?