Very odd, but I have seen something similar with other Cloudflare sites when accessing from Chrome too. I am wondering whether there is something odd at our side and so have asked internally.
It would be great if you were using Chrome and could confirm it still happens once per day, and when it does a screenshot of the Chrome page (which is more informative than the IE generic error page).
In which case this could be a TLS1.3 issue as your workplace proxy possibly isn't happy with it.
You can disable TLS1.3 in Firefox and see if that solves it... but it's probably better to leave it enabled and just to deal with the refreshes when this happens.
Very odd, but I have seen something similar with other Cloudflare sites when accessing from Chrome too. I am wondering whether there is something odd at our side and so have asked internally.
It would be great if you were using Chrome and could confirm it still happens once per day, and when it does a screenshot of the Chrome page (which is more informative than the IE generic error page).