Unable to get planner details associated with a group

[JinT]

Hi All,

I am trying to get Planner details for a group/team, below is my script. I have registered the app and it has all permissions:

Group.Read.All
Group.ReadWrite.All
Tasks.Read
Tasks.ReadWrite

User.Read

User.Read.All

yet it keeps giving me error "You do not have the required permissions to access this item"

$clientId = "[clientId]"  
$clientSecret = "[clientSecret]"  
$tenantName = "testtenant.onmicrosoft.com"  
$resource = https://graph.microsoft.com/  
$groupId ="5a987e93-d3db-4fde-96d0-f1a60ac2bd58"

  
$tokenBody = @{  
    Grant_Type    = "client_credentials"  
    Scope         = https://graph.microsoft.com/.default  
    Client_Id     = $clientId  
    Client_Secret = $clientSecret  
}   
  
$tokenResponse = Invoke-RestMethod -Uri https://login.microsoftonline.com/$TenantName/oauth2/v2.0/token -Method POST -Body $tokenBody  

Connect-MgGraph -AccessToken $tokenResponse.access_token
Get-MgGroupPlannerPlan -GroupId $groupId

I cannot define scope in the script using Connect-MgGraph -Scopes 

Can please anyone let me know if I am missing anything ?

Thanks In Advance

[#2]

Planner only supports delegate permissions, you cannot use the client credentials flow.

[#3]

Thanks for your reply, the azure app already has delegate permissions, if you are referring to something else, please can you give a reference link.

[#4]

The code sample you pasted above uses the client credentials flow, this results in getting a token in the application permissions model, not delegate one. Use the auth code/on behalf of flow instead.