Statring in iOS 9.0.0 Apple added a new feature called Wifi Assist to automatically switch to cellular when a mobile device has a poor Wi-Fi connection.
With Wi-Fi Assist, you can stay connected to the Internet even if you have a poor Wi-Fi connection. For example, if you’re using eKeypad with a poor Wi-Fi connection and it is unable to connect, Wi-Fi Assist will activate and automatically switch to cellular so that it can connect.
Wi-Fi Assist is enabled by default.
Obviously this can make troubleshooting very complicated. it is recommended to disable Wifi Assist whenever you are trying to resolve connection issues with eKeypad.
To disable Wi-fi Assist start by opening up the iOS Settings application. Scroll down and select the Cellular link. Then scroll down and tap the slider for Wi-Fi Assist. This change takes effect immediately.