Help & troubleshooting for channels on your Roku device, including adding/removing channels, logging in to, authenticating, or activating a channel, channel-specific playback issues, assistance contacting channel publishers to report issues, and adjusting channel-specific settings.
Exiting any app via the HOME button isn't a problem in and of itself. It's how many people exit apps. It's how I've always done it (since 2010). It's the quickest and easiest way to exit any app.
Now, the failure to save login is an issue. If it won't save the login, try 1) removing the app, 2) rebooting the Roku, then 3) reinstalling the app and trying again. Note, you must perform all three steps in that order.
DBDukes Roku Community Streaming Expert Note: I am not a Roku employee.
If this post solves your problem please help others find this answer and click "Accept as Solution."