Blog Post returning error page in Safari and Chrome

I have a problem with a single blog post (out of many) that’s returning the error page in both Safari and Google Chrome.
It’s just one article from the entire website.
How it happened:
I was replying to a comment as admin when, WP automatically logged me out from admin, in a different tab. I did not notice and hit post. The comment wasn’t posted an error was generated saying that I am logged out. I logged-in back as admin but when I refreshed the page with the comment in returned an error page on Google Chrome.

This site can’t be reachedThe webpage at https://www.iphonetricks.org/ios-10-adds-recent-label-next-to-iphone-contact-number/ might be temporarily down or it may have moved permanently to a new web address.
ERR_FAILED

I cleared the cache of the browser and also of the website, no success that page still doesn’t load.

I tried to access it via Safari from iPhone and I get this error only on the same page, that I hadn’t visited before from this device. The error reads:

Safari cannot open the page
The error was:
“FetchEvent.respondWith received an error: Returned response is null.”

When I search Google for this error the results say that it’s PWA related.

Any idea how I can fix this? Are you able to access the above mentioned url?

Thanks

The page I need help with: [log in to see the link]