"The request body must contain the following parameter" error

Question

I'm trying to get AAD token then get Yammer message using Yammer API but I'm getting this error:

Invoke-RestMethod : {"error":"invalid_request","error_description":"AADSTS900144: The request body must contain the following parameter: 'code'.\r\nTrace ID: b4f13dec-5b00-446d-b6b0-9b03e1de2700\r\nCorrelation ID:
61ff7b84-22eb-4176-a7e9-eec721c73d60\r\nTimestamp: 2023-07-26 14:59:00Z","error_codes":[900144],"timestamp":"2023-07-26
14:59:00Z","trace_id":"b4f13dec-5b00-446d-b6b0-9b03e1de2700","correlation_id":"61ff7b84-22eb-4176-a7e9-eec721c73d60","error_uri":"https://login.microsoftonline.com/error?code=900144"}
At line:18 char:15

I added "code" inside the body but how can I get the $authorizationCode?

$ClientId = ""
$SecretID = ""
$tenantid = ""
$params = @{
    Uri    = "https://login.microsoftonline.com/$($tenantid)/oauth2/v2.0/token"
    Method = "POST"
    Body   = @{
        "client_id"     = $ClientId
        "client_secret" = $SecretID
        "grant_type"    = 'authorization_code'
        "code"          = $authorizationCode
        "scope"         = "https://api.yammer.com/user_impersonation"
        "username" = "";
        "password" = "";
    }
}

$connection = Invoke-RestMethod @params
$headers = @{ Authorization=("Bearer " + $connection.access_token) }
$webRequest = Invoke-WebRequest –Uri "https://www.yammer.com/api/v1/messages.json" –Method Get -Headers $headers

if ($webRequest.StatusCode -eq 200) {
    $results = $webRequest.Content | ConvertFrom-Json

    $results.messages | ForEach-Object {
        $message = $_
        Write-Host $message.sender_id $message.body
    }
}
else {
    Write-Host "An error has occurred: " + $webRequest.StatusCode
}

Answer 1

The error occurred as you are not including $authorizationCode value in your PowerShell script that is needed to get token using authorization code flow.

I registered one Azure AD application and granted consent to Yammer API permission:

When I ran your PowerShell script in my environment, I got same error as below:

To resolve the error, you need to get code value by running authorization request in browser for which redirect_uri is needed.

I added redirect_uri as https://jwt.ms in Authentication tab of Azure AD application:

When I ran below authorization request in browser, I got code value in address bar after signing in:

https://login.microsoftonline.com/tenantID/oauth2/v2.0/authorize? 
client_id=appID
&response_type=code  
&redirect_uri=https://jwt.ms
&response_mode=query  
&scope=https://api.yammer.com/user_impersonation
&state=12345

Response:

Now, I ran below modified script by adding code value and got response successfully:

$ClientId = "appID"
$Secret = "secret" 
$tenantid = "tenantID"

#Make sure to include this variable with code value
$authorizationCode = "paste_code_from_above_request"

$params = @{                
    Uri    = "https://login.microsoftonline.com/$($tenantid)/oauth2/v2.0/token"
    Method = "POST"
    Body   = @{
        "client_id"     = $ClientId
        "client_secret" = $Secret
        "grant_type"    = 'authorization_code' 
        "code"          = $authorizationCode 
        "scope"         = "https://api.yammer.com/user_impersonation"
        "redirect_uri" = "https://jwt.ms"
    }
}
 
$connection = Invoke-RestMethod @params

$headers = @{ Authorization=("Bearer " + $connection.access_token) }
$webRequest = Invoke-WebRequest –Uri "https://www.yammer.com/api/v1/messages.json" –Method Get -Headers $headers

if ($webRequest.StatusCode -eq 200) {
    $results = $webRequest.Content | ConvertFrom-Json

    $results.messages | ForEach-Object {
        $message = $_ 
        Write-Host $message.sender_id $message.body
    }
}
else {
    Write-Host "An error has occurred: " + $webRequest.StatusCode
}

Response: