Vanilla Version 2.6.4
Maintenance Mode Addon regretfully not working or suffering interference from other plugins
Update: I installed "Maintenance Mode" in a fresh 2.6.4 installation. It Worked
So, as I mentioned, in my case it is suffering interference from other plugins, locale extenders or applications.
I'm really unsure why anyone would use this addon. Vanilla supports maintenance mode with a simple config setting. This 8 year old addon is unnecessary.
FYI this Plugin is maintained in a GitHub repository in case anyone wants to contribute: https://github.com/oliveratgithub/vanillaforums-MaintenanceMode
i might look into it ASAP myself, no promise though.
@charrondev I think the nice thing about having a plug-in is you can enable & disable with a click in the backend, rather than having to edit config files manually. However, I also think the maintenancemode plugin should not hack the page rendering but make use of this configuration setting...