The app is not supported by the OS on the phone or tablet.
The app may be in the process of being evaluated to ensure compatibility with your OS.
If you are using a newer version of the OS that does not yet support the app, you will not be able to go back to a previous version of the OS.
Check the list of supported phones or tablets at the following website: www.mclheart.com
Talk with your heart doctor for more monitoring options.