I’m not sure what to tell you. I can’t tell you any more about the user other than what I’ve said so far (although looking at the screenshot, it looks like IE11 running Win 8.1).
As for me, I loaded up the IE11 Win8.1 VM from https://www.modern.ie/en-us/virtualization-tools, went to the site, hit sign up, completed all the questions (getting all the green ticks as I went) then upon hitting submit button, i get redirected to a blank screen. This happened on both Birmingham.IO and this site.
I’m still confused as to why try worked, while meta and Birmingham.IO didn’t, but this is a step in the right direction.
I’ll run Windows update in the VM and see what happens, and ask my user to run Windows Update too (although I don’t think she’s inside a VM, but it would not surprise me if she was a patch or two behind on Windows).