Existing API send to message with Obtain an Access Token

[Viet_Bui_Tran_Thien]

how can I send message existing conversation.
I reseached on api-explorer Ad found the api:

• POST /api/v2/conversations/messages/agentless

• POST /api/v2/conversations/messages/{conversationId}/communications/{communicationId}/messages

Can I use those apis to send message with Obtain an Access Token?
I try to test with second api, but it is failed

{
    "message": "This request requires a user context. Client credentials cannot be used for requests to this resource.",
    "code": "bad.request",
    "status": 400,
    "contextId": "139f3cb2-8e7c-4bd5-892c-51ff94a6dfdf",
    "details": [],
    "errors": []
}

Thank you Team so much

[Greg_Boston]

@Viet_Bui_Tran_Thien you can use Agentless API for several messaging channels. This guide walks through the process for sms channel sms-notification-guide you can take that information and apply it to Whatsapp or Open messaging too.
As far as the "token" part of your question, I'd need more info as I don't understand the question.

[Viet_Bui_Tran_Thien]

@Greg_Boston

Open messaging too.

Can I use the Agentless api for webmessaging channel ?
as far as i know this api is not supported anymore?
please confirm this for me
about token, I meaning, I can use api https://login.mypurecloud.jp/oauth/token to get token, right ?
Thank you so much.

[Greg_Boston]

Agentless api doesn't support WebMessaging at this time, no. It has never been supported yet, so it's not "anymore" situation.
I'm still a little unclear specifically what you are asking about for the token question. But did you review the page I linked already? Did you see it has a link to this other page describing how to create the Oauth client create-an-oauth-client You would take that Oauth client you created and use it to generate a token to use to call the Agentless api, see oauth-client-credentials-guide