Hi all,
I'm try to add a default group to the SharePoint site visitors with Power Automate.
I'm trying it to do it with the follow HTTP request to SharePoint, but it's not working and I didn't know why/what's the issue is:

I found this thread: Solved: Add specific o365 group to a SharePoint Site Permi... - Power Platform Community (microsoft.com)
But where @mousman85 is using:
'LoginName': 'c:0t.c|tenant|<Group OBJECT ID>'}
I don't know what "c:0t.c|tenant|" means, but it's not working for me.
I'm trying to put only my group Object ID, but it is not working.
I receive the error:
"User doesn't exists or not unique"
If I test with the follow setting to add a single user it's worksfine:
{
"__metadata": {
"type":"SP.User"
},
"LoginName":"i:0#.f|membership|emailadres@ofasingleuser.com"
}
But it is not working with a group mail adres or groupobjectID.
Anyone know how to fix this?