VladTheGreat

It's hard to explain in a sentence but if crawler accesses though guest, the bot follows links only avail to guest so if you use a crawler app to crawl your website as guest and see where it's able to go, youll see where your permissions could be at fault? Hope it helps

is he using VPN with changing I.P or from a static one?

I know this is an old thread but I wish I seen it sooner, the answer is in your permission settings, the problem I find is that modules and menus in IPS have separate permission tabs, you might allow a crawler to crawl the "Classified" section, but at the same time restrict the menu link to be seen to guests or visa versa etc, you must check that you allow the robot to see everything you've linked from public menues also to avoid landing page link following errors, if menu isn't visible to a crawler it can't error on a path it can't see to attempt travel on etc. Also, avoid static ads, always use auto sizing ads for ips4 :)