How to generate the authorization code and the access token to embed Powerbi in WebApplication

Hi,

Have you checked the following article?

How To: Get embed token using Get/Post only

The call to generate Access Token should be

"

POST: https://login.microsoftonline.com/common/oauth2/token
data: {
    grant_type: password
    scope: openid
    resource: https://analysis.windows.net/powerbi/api
    client_id: {Client ID}
    username: {PBI Account Username}
    password: {PBI Account Username}
}

--Returns Json:
 
{
    "token_type": "Bearer",
    "scope": "Report.Read.All ...",
    "expires_in": "xxxx",
    "ext_expires_in": "0",
    "expires_on": "xxxxxxxxxx",
    "not_before": "xxxxxxxxxxx",
    "resource": "https://analysis.windows.net/powerbi/api",
    "access_token": "eyJ0eXAi...",
    "refresh_token": "AQABA...",
    "id_token": "eyJ...."
}

"

The resource should be 

https://analysis.windows.net/powerbi/api

Make sure you have specified the other data part correctly.

for the process, please also check the document below:

Step 2: Get n authentication access token

Regards,

Michael