Coming Soon Page not coming up

I just installed a new theme on my website and then installed the WP Maintenance mode plugin. I created a ‘splash’ page and activated the maintenance mode but the URL still goes to my website (which is a mess because the themes are not compatible – which is fine).

Does this take time to activate or is there a possibility of incompatibility?

Help!

https://wordpress.org/plugins/wp-maintenance-mode/