Preview Images Stopped Loading

Hi,

I have recently enabled SSL on my WordPress website. I have implemented Cloud Flare on my website and followed these 2 tutorials to make it working:
https://www.icontrolwp.com/blog/enabling-cloudflares-universal-flexible-ssl-wordpress-without-infinite-redirect-loops/
https://jonnyjordan.com/blog/how-to-setup-cloudflare-flexible-ssl-for-wordpress/

Unfortunately my preview images have stopped appearing. I have setup a test page here- https://www.headerlove.com/test-page/ The images added in posts/pages appear fine but not the preview images.

Any help would be appreciated.