Do you get much choice as to what goes onto your PC (can you try Chrome or Firefox) ?
Do other colleagues get the same message when they try the site ?
From memory (I haven't got a Windows machine in front of me), there is also a 'Compatibility Mode' in the browser menu under Tools - might be worth trying that ?
It looks like there could be any number of causes, search engine results advocate messing around with the Internet Options control panel to tune various settings (I'd be reluctant to mess with those in case they interfere with your access to systems required as part of your work) - seems a little odd that mu-43 works but this site doesn't tho'.
If it works for other colleagues or if you log into another computer within the company and it works then it may be a side effect of migrating your user-settings over to the new Windows 10 machine. If they (your IT team) didn't migrate your settings & files over and you're starting with a new login profile then theres something else happening.
If it doesn't work for other work-mates on different computers then it would be some kind of enterpise-wide setting or restriction occurring. On the other hand, if one of your colleagues were to login to your machine and it works (or it works for them on their machine), then it is something unique to your user-settings or login-profile.
Unfortunately with these types of issues it is often a matter if working through the variables and isolate what does/doesn't work.
It could be a side affect of firewall changes. They muck about with our firewall and internet security settings here all the time. Some days, I can get to Flickr, others not.
Our support tech says that they have a subscription to third party services that rate sites for things like language, adult content and if those services deem a site fall within certain criteria, then the filter service will block the URL. If, when the third party product re-evaluates the site, it may deem it safe, and open it up.
Other things that out network support teams has is a tool that scans URLs and it has specific words that it has on a block list.
It is possible that words like "cafe' and "cameraderie" hit too close to the algorithms "no-no" words.
For that reason, I bring my own machine to work for use on these forums and either tether to my phone or use a VPN.
This may not be your issue, but it is something to rule out.