Q: I am owner/manager of CTA e-group MYGROUP, which is managed by the SharePoint portal. When I receive requests from a new member to join MYGROUP, I follow the link to validate the request, but am redirected to a page which tells me "Error: Access Denied".
A: Unfortunately this is a longstanding issue. It is a fake error, because the redirection after the successful validation goes to a page, which is only accessible to site administrators. Therefore:
And usually you will find that the new member has been added to (or removed from, in case of a leave request) the MYGROUP list.