如何解决Page Speed Insights上的“后端错误”以优化我的wordpress网站?

I have been working on optimizing my website and was able to bring up the GTmetrix score from a D to an A. However when i run the tests on page speed insights i receive a "backend error" message. Any other site i test works fine except for mine. My site URL is jasminnoir.com.au

I have added headers expires, using CloudFlare and other optimization code, both speed and YSlow scores are an A on GTmetrix. All page speed sites work except for page speed insights. How can i fix this?