Hi @andywest,
Sorry to hear about the issue you experienced.
WordPress itself automatically activates Maintenance Mode when updating plugins/themes and such; but if the update process is interrupted (e.g., due to a slow server, internet disconnection or similar), the .maintenance file might not be removed from the root folder of your WordPress site (same folder as the wp-config.php file) causing Maintenance Mode to persist. If you manually remove that file, Maintenance Mode will be disabled.
The 301 redirect to HTTPS has always been one of the core features of this plugin since it’s release, and should of course work without any such issues. If you need any assistance with setting it up, feel free to open a thread on the Support Forums of this plugin (https://ww.wp.xz.cn/support/plugin/really-simple-ssl/) as we would be more than happy to take a look at the issue.
Kind regards, Jarno