Preload not working

Hi! Seen a few posts re this issue but none appear to help me. Currently testing on one of my Demo sites (only 5 pages). On activating preload, I then clicked the Preload Cache Now Button. Once clicked, the page (after refreshing) then displays Preload is active and currently caching from post 0 to 100, then the last page cached, or in my case, a URL to part of my Elementor page builder Header i.e. https://www.mywebsite.co.uk/?jet-theme-code-header=header. At this stage, it also sends an email to confirm preloading has started. Although i then received an email to confirm preload is complete, in the Preload Tab, it still had 0 to 100 posts and teh same URL. After refreshing the page, it then gave details of teh next preload (30 mins in my case for testing purposes). At this stage, I went to the Content Tab and clicked the Regenerate Cache Stats link. There were 0 cached pages! After about 10 minutes, probably after my manual scheduled cron job has been run (every 10 mins), I then went back to teh Content Tab and regenerated the Stats. This time, it just had the Homepage as being cached. Anyone have any ideas what the issue may be?

Using Simple Cache Delivery, Disable for logged in users, Compress pages, Cache Rebuild and 304 Browser Caching. Cache timeout 36000 sec, Check stale Cache 36100 sec.