Problem with 1 Mac (out of 4 different Macs) having issue connecting to Airplay In our office we have an AppleTV 4th gen, 32gb, hardwired to our switch which in turn is hardwired to our router. 

For Wi-Fi we have a Ubiquiti access point hard wired to the same switch as the AppleTV. 

For 3 users running a mixture of Yosemite and Sierra connecting, disconnecting,  etc. from the AppleTV when their computer is connected to Wi-Fi works fine. 

One user always has issues where they can connect. The icon in the top bar goes blue, and the AppleTV either stays on the home screen or goes black, but their screen is not mirrored. Sometimes it connects fine, but sometimes it doesn't. 

Info on the Mac in questions : 


Mid 2012 MacBook Pro 13" (non 4k, one of the last ones with user upgradable RAM)
i7, 16GB RAM
Was running Yosemite, so I upgraded them to Sierra, but the problem still persists. 
The Mac itself doesn't seem to have any other Wi-Fi related issues. In fact, often when the issue occurs the Mac is connected to Wi-Fi, running Google Drive,  Dropbox, etc. absolutely fine.


The Wi-Fi AP is a Ubiquiti UAP AC PRO c. 450mbps 2.4ghz throughput, c. 1300mbps 5ghz throughput.

At all times the laptop is &lt;6m away from the AP. All other devices that work fine on the Apple TV connect to the same access point and have no issues. At most there are &lt;10 concurrent devices (inc. phones and tablets) connected at any one time, but usually one or a few devices are active (eg. currently connected and being actively used for browsing etc.).

Any ideas ?
I have not been able to fix the problem, after about 3 hours of trying. 

Fortunately i found a work around which is Airparrot, it seems slightly counter intuitive to use a 3rd party app to run an native OSX function when speaking to another Apple product, but it works really well on the machine i was having an issue with.