OnSong is designed to be used for completely disconnected with any Internet access. This is by design to make sure the app is as robust as possible and to allow musicians to play in any environment. When you import your songs and content into OnSong, it's stored on the device.
Of course like any modern app, OnSong integrates with web-based services. If you are disconnected from the Internet or WiFi, some services are simply not available. For instance, you cannot import song files from Dropbox if you are not connected to the Internet since OnSong pulls that content directly from the "cloud". Likewise, while OnSong will let you compose an email to send to your team for sharing sets, the email will not be able to be sent until a network connection is reestablished.
When a network connection is disrupted, OnSong automatically disables these features and may grey out these services. However, the app will continue to function without error messages to allow the user to continue playing music in live scenarios.
While OnSong provides access to streaming content like Apple Music, it is important to take network performance into account when using these resources in a live environment. We recommend downloading or caching this content on the device when possible to avoid interruptions due to an outage during your performance.