If the app loses connection, it is typically the connection between the hearing aids and the mobile device that has been lost. A small red badge on the Connectivity button will notify you that the connection is lost. Go to the Connectivity screen and tap the marked point of lost connection for guidance on how to re-establish the connection.
It is also a good idea to turn off the Bluetooth on your mobile device and turn it on again. On most mobile devices, this can be done in a control panel by swiping up from the bottom of the screen (Apple), or down from the top of the screen (Android). Tap the Bluetooth icon to turn it off, wait a couple of seconds, and then tap it again to turn it on.
If this does not work, please try turning the hearing aids off by placing them in the charging case or opening the battery doors, then restart your smartphone. Once your phone is fully powered back on, you may turn on your hearing aids again.