If you experience connection issues between your Android phone and your Arsenal, please try the following. The OS on most Android phones is customized by the carrier and manufacturer, so the location of options varies from phone to phone.
1. Usually located in advanced wifi settings, you'll find a setting with one of the following or similar label:
"Switch to mobile data"
"Auto network switch"
"Automatically switch network"
Android is detecting that there's no internet on the Arsenal wifi network and trying to switch to a different network. Turn that setting off.
2. A second option that works on some phones is to disable mobile data. Go into your Settings>Connections>Mobile Data and toggle mobile data off.
3. Lastly, if none of the other options work, try also forgetting your local WiFi network. Android may attempt to change to your local WiFi network since it expects it to have a stronger internet connection, even if you're not in range of your WiFi network.
In the meantime, please check out the new Arsenal with Android setup articles if you haven't seen them already: