ORBI 850 issue with iPhone app

Ya, your experiencing 3rd party mfrs limited development and design on there apps to only work on 2.4Ghz, not thinking maybe or realizing that most phones and pads are dual band supporting devices and most of these devices prefer to connect to 5Ghz vs 2.4Ghz. Also these Mfrs fail to realized that both 2.4 and 5Ghz are on the SAME network as well. So even if there devices only connects at 2.4Ghz, the setup phone and setup app could connect to 5Ghz and still would be able to see the target device on 2.4Ghz. I find it amazing that these Mfrs won't just add 5Ghz support on there setup app to allow the setup mobile device to connect to any frequency and still be able to setup the target device on 2.4Ghz. But you know, everything is done on the cheap rather then going the extra mile to provide better app and device support on newer generation wifi MESH systems that are designed to support only 1 SSID name broadcast for both frequencies. 

So you can try this. Turn OFF the RBS. 

Use a pc and web browser and log in to the RBRs web page. 

Turn down the power output of the RBRs wifi radios from 100% to 25% and apply the change. Under Advanced Tab/Advanced Settings/Wireless Settings

Disable the wifi radio on your phone or pad temporarily. You'll need to walk out from the RBR location aways, then turn ON the mobile devices wifi radio and hopefully it will connect to the 2.4Ghz radio since it can travel farther then the 5Ghz signal. If you can get it connected on 2.4Ghz, get the target device set up. If you can get it setup, then return the RBR transmit power back to 100% and then turn ON the RBS.