unable to provide consent

Hi All,

I am facing an issue with API permissions. I have an Azure App Registration with the following Microsoft Graph API permissions. Let's say the App Registration name is TESTAPP and the Client ID is xxxx-xxxx-xxxxx-xxxxx.

I have a SharePoint site, let's say mysite1, and I am trying to provide permissions in the following way:

I obtained the site ID using the following URL:

https://mydomain.sharepoint.com/sites/mysite1/_api/site/id. Let's say the site ID i got is

11111-111-1111-11221

i have logged into https://developer.microsoft.com/en-us/graph/graph-explorer/

Post-->v1.0-->https://grapsh.microsoft.com/v1.0/sites/{11111-111-1111-11221}/permissions

Request headers: Key:application/json

Request Body:

{

"roles": [

"write"

],

"grantedToIdentities": [

{

"application": {

"id": "xxxx-xxxx-xxxxx-xxxxx", # This is my app regisration id

"displayName": "TESTAPP"

}

}

]

}

When i click modify permissions and search for sites permissions, i am unable to provide consent, its grayed out. I am a global admin and i have full access on the SharePoint site. Please guide me.