Orbi Connection problem

Hi

Installed the Orbi system and it works great in our three level house, even in previously problematic areas.

I have a weird problem though. The entire downstairs area where the Orbi router is located gets  full signal on all devices: Macbook Pro, Macbook, Iphone, Galaxy tab, Dell laptop etc. 

All devices connect and run just fine except the Macbook 12" in one of the rooms. It is a brand new machine, bought late in 2016. It works perfectly on other wireless systems (belongs to my daughter and connects at school and worked with my previous wifi setup etc). 

In the one room that is her study the Macbook connects to a full Orbi signal with three bars but there is no internet until I walk out the door. Signal strength is 100% the same but the Internet conenction does not work at th desk. All other devices work 100% at this desk, I am writing this from the same spot using my Macbook Pro and everything is fine. My galaxy tab is perfect from this position as well.

The problematic device is a 12 in Retina Macbook, Late 2016. It sees three full bars, connects fine, but no internet. Once you walk into the hallway the internet works, btu after a couple of minutes back in the room the internet is gone, btu you still have ful bars. 

I am in Australia. Any help will be greatly appreciated. I'd hate to run a  repeater off a second network for just one room.