[BUG] Grant-PnPAzureADAppSitePermission error

[xeayabe]

Reporting an Issue or Missing Feature

Please confirm what it is that your reporting

Expected behavior

I created an app (App1) with SiteSelected.All, aiming to grant access to a specific SharePoint site. I connected to my PnP azure (App 2), which has these permissions:

Then, I used it to run this command:
Grant-PnPAzureADAppSitePermission -AppId $App1-DisplayName "NameOdMyApp" -Site $siteUrl -Permissions Write

However, I received this error:
{"error":{"code":"accessDenied","message":"Access denied","innerError":{"date":"2025-06-24T16:12:01","request-id":"xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxxxx","client-request-id":"xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxxxx"}}}

Either I use App1 or App2, I can read and write files, but only with PnP commands like Get-PnPFile, Add-PnPFile, or Get-PnPFolderItem. However, I’m unable to perform any actions when using APIs.

Actual behavior

I also run in graph explorer (as I read online) the following but it didn't work:
(https://graph.microsoft.com/v1.0/sites/tenantname.sharepoint.com,xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxxxx,xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxxxx/permissions)

{
"roles": ["write"],
"grantedToIdentities": [
{
"application": {
"id": "x-xxxx-xxxx-xxxx-xxxxxxxxxxxxx",
"displayName": "MY_APP"
}
}
]
}

And it successfully created, but i am not able to make it work:

Steps to reproduce behavior

$tenant = "name"
$secPassword = "secret" | ConvertTo-SecureString -AsPlainText -Force
$certname = "certname"
$AdminCenterURL = "https://tenant-admin.sharepoint.com"

$clientId = Get-Content "path\ClientID.txt"
$certFilename = "path\$certname.pfx"
$siteUrl = "https://$tenant.sharepoint.com/sites/sitename"
Connect-PnPOnline -Url $siteUrl -ClientId $clientId -Tenant "$tenant.onmicrosoft.com" -CertificatePath $certFilename -CertificatePassword $secPassword

$appId = "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxx"

Grant-PnPAzureADAppSitePermission -AppId $appId -DisplayName "AppName" -Site $siteUrl -Permissions Write

What is the version of the Cmdlet module you are running?

(you can retrieve this by executing Get-Module -Name "PnP.PowerShell" -ListAvailable)

Which operating system/environment are you running PnP PowerShell on?

• Windows