Thanks for writing in!
I checked the website and looks like you are using Cloudflare CDN. I suggest you to please clear Cloudflare CDN cache and put Cloudflare to development mode. Next, I also suggest you to test for plugin conflict by deactivating all plugins and reactivating one at a time to narrow down, specifically test for Jetpack plugin as I see that on website you are using Jetpack.
If above solution don't work out, please try increasing the memory limit. For instruction on the same, please refer following tutorial.
If you still have problems kindly get back to us with the result of the steps above and URL/User/Pass of your WordPress dashboard using the Secure Note functionality of the post to follow up the case.