To get your Spire to reconnect, try running through each of these steps in succession until it pairs:
Try turning OFF your Bluetooth and then turning it back ON through the Settings icon on your iOS device. To do this, tap on the "Settings" icon. On the next screen, tap on "Bluetooth" then slide the Bluetooth button OFF, wait 10 seconds, and then turn it back On again. When you turn it back on go back to the Spire App and make sure that it has paired once again.
Try closing the Spire app. Double click on the Home button. This will display all the apps currently running. If you see the Spire app, swipe UP on it to close it. Try running the app again and see if it re-connects.
Power Cycle your iOS Device. Shut it down and then try restarting it.
Try resetting your network connections on your iOS Device. This will reset your phones Wi-Fi, VPN and Bluetooth connections. You will need to rejoin these networks and devices and know the passwords to re-join them. Go to the "Settings" icon/app on your iOS device then scroll down to "General". While in the "General" tab, scroll down to the bottom and click on "Reset". On the next screen tap on "Reset Network Settings". After you initiate the reset try running the Spire app again.
Also, Spire will only pair with ONE host device at a time. Spire is unable to be paired simultaneously to multiple devices.