What is not working? The site loads fine on HTTPS, there is a mxed content issue but that is not certificate related. The certificate seems to be fine.
It would seem your DNS resolver still uses some cached values and does not return Cloudflare’s IP addresses. Wait a bit or try to flush its cache, if you have access to it.
If you just changed it from to there is a good chance you resolver still caches the original IP. Wait a bit until that value expires and it renews the entry. At that point you should get the site loaded, you still have mixed content issue though.