Unfortunately, this is not possible - Host must have at least one authentication method enabled and set up. You can choose and set up any of them that works for you - e.g. Single Password, RU Security, Windows Security, etc. Please see this page for more information on authentication methods available.
Could you please try entering your full email address into the "Username", "From email" and "Destination email" fields (for example, [email protected] or [email protected])? You can refer to this guide for more detailed instructions on setting up an SMTP server.
The Remote Printing feature was not discontinued, it should still be available in the latest version. Please try checking if you have the printer driver installed on your Host machine: you should be able to locate it in Windows Settings→Bluetooth & Devices→Printers & Scanners as described here. and try uninstalling and reinstalling it in the Host Settings -> Other tab. Please make sure to restart Host after reinstalling the driver for the changes to be applied.
Could you please verify that you’ve updated both Host and Viewer (as well as RU Server if used) to the most recent version 126.96.36.199 (and version 188.8.131.52 for RU Server respectively)? If all modules are already updated, but the issue still persists, please feel free to send us the most recent log files - you can send them to [email protected].
The Host service might have been uninstalled as a result of some antivirus software activity. You can add the Host installation folder to the exception list as described here and also submit a false positive report to your a/v vendor - this should help to resolve the issue with uninstallation and, hopefully, prevent it in the future. After you add the Host folder to the exceptions, you should be able to re-install Host via AD or try the solutions listed on this page.