Slack bot send message to chat and faced with not_in_channel error

I created my app and then follow to send button tutorial (I replaced client_id to ########)

Add to Slack

then follow by this redirction and click allow

after success get code in redirect_uri I used it on oauth api V2, I got this response (I replaced real data to #######)

https://slack.com/api/oauth.v2.access

    {
    "ok": true,
    "app_id": "#######",
    "authed_user": {
        "id": "#######"
    },
    "scope": "chat:write",
    "token_type": "bot",
    "access_token": "xoxb-#######",
    "bot_user_id": "#######",
    "team": {
        "id": "#######",
        "name": "#######"
    },
    "enterprise": null,
    "is_enterprise_install": false
}

so then after that I grab access_token from that response I try to execute post message is some channel in workspace (in response this is team info)

$response = $this->client->request('POST', 'https://'.$this->getEndpoint().'/api/chat.postMessage', [
    'json' => array_filter($options),
    'auth_bearer' => $this->accessToken,
    'headers' => [
        'Content-Type' => 'application/json; charset=utf-8',
    ],
]);

and I faced with repult like that,

$result = {array[2]} 
 ok = false
 error = "not_in_channel"

so what I'm doing wrong ? how to force bot send message in some channel from my workspace which was allow scope for current bot(app) by slack button suggestion ?