Impacted versions:

8.0

Steps to reproduce:

To reproduce this one, you have to configure outgoing and incoming server and mail aliases

see https://youtu.be/-HzDGh9C9Jc

Current behavior:

If you add a user which has no acces on a object (purchase.order in this case) as follower on a record of this object **AFTER someone has responded by email on this record**, and if you send an message on this record, an exception is raised at the connection of the user added as a follower.

Expected behavior:

No exceptions should be raised at the connection of the user added as a follower.

Video/Screenshot link (optional):

https://youtu.be/-HzDGh9C9Jc

return {
                'domain': domain,
                'nb_messages': message_nb,
                'type': 'expandable',
                'parent_id': parent_id,
                'max_limit':  max_limit,
            }
        if not messages:
            return True
        message_ids = sorted(message_tree.keys())
        
        if thread_level == 0:
            exp_domain = domain + [('id', '<', min(message_unload_ids + message_ids))]
        else:
            exp_domain = domain + ['!', ('id', 'child_of', message_unload_ids + parent_tree.keys())]
        more_count = self.search(cr, uid, exp_domain, context=context, limit=1)
        if more_count:
            
            if parent_id:
                messages.insert(0, _get_expandable(exp_domain, -1, parent_id, True))
            
            else: