What's happening is normal because of your page's performance (see secure note). Your page eventually loads completely but because your page is heavy with scripts and animations. There's a lot going on in your page.
Measuring the performance of your page took a very long time that I aborted the process.
Just loading your page made my computer lag because it's taking a lot of memory.
This is not an issue with ConvertPlus. This is an issue with your site's performance. You need to reduce the scripts in your site. That means you need to remove features in your site that slows a page down like your background sound and scripts especially animations. It's not for us to decide what's good for your site though. This is your responsibility to manage.
Regretfullly, we could not help further with this issue.
Thank you for understanding.