Onpage.org Indexability Suddenly not working

Hi, I know this was checking out fine before, but now it says it can’t fetch the status. I checked with my webhost provider and they said

“Upon reviewing the page at http://kb.yoast.com/article/318-indexability-check-doesnt-work, we confirmed that our servers do not have the connectivity issue as described on the page. There is also no special “white list” as per point #2.”

Is there anything else I can check to see why it’s stopped working?

https://wordpress.org/plugins/wordpress-seo/