Installed Genie for Android, now phone won't connect to wifi network

OK, this is a strange one. About a month ago I installed a new R6400 router. Assigned the same SSID and password that were already in use so I wouldn't have to reconfigure about a dozen devices. Everything, including two Galaxy S5 phones, worked flawlessly.

Then, after a week or so, I installed the Genie Android app on one of the Galaxy S5 phones. Started the app, successfully connected to the router, and everything still seemed to be working as it should. However, the next day, the phone that had Genie installed quit connecting to the 2.4 GHz wifi. (Every other device, including the other identical phone, continued working fine.) It would hang at the "obtaining IP address" step, then show an unhelpful message about the AP not being in use. Uninstalling the Genie app and rebooting the phone did nothing. The only thing that would restore the wifi connection was found on a Verizon support forum: Turn off wifi on the phone; shut down phone; remove battery and SIM card; then reinstall SIM card and battery and power on phone. The 2.4 GHz wifi connection then started working again, and worked perfectly for several weeks.

To see if I could duplicate the issue, I again installed, but did not run, the Genie Android app. The phone continued to connect to wifi perfectly. After several days I ran the Genie app, and sure enough, within an hour or two the phone's wifi again quit connecting. This tells me that the Genie app is the cause of this problem. I'm just leaving the app off both smart phones until I can find a solution.