Can you tell me how you posted your group in a link that?
The original link is at the very top thread and I think re-posted a little further down.
It may be a little confusing. as when you do post a link, or when you see the link, it has the appearance as if it were a normal personal invite link.
@ISh98 has kindly posted a screenshot And described of the location of the group invite link.
Hopefully, you should have it sorted by the time you read this anyway