I get the error shown below while browsing on Firefox. If this is not the right place, let me know; it says to contact the website owner.
As requested, the visible link in the screenshot is: How do the different propeller configurations compare for wind tunnel purposes? (Title has changed since.)
However, the post worked fine after trying again, and it didn't happen just the once (different posts/pages).
If it is not just a Firefox issue, feel free to update the tags.