I have the same problem. I have enabled Flash player and updated windows 10 and it still isn't working. I'm in the middle of online studies and it was working until the Windows 10 update I put on my Laptop. I have also disabled the Firewall and I have checked that I have it, I can see the test picture on your website
I branched your post to a new topic as it doesn't sound the same as the issue you posted to, where the OP was attempting to view downloaded Flash files and you don't mention this in your post.
Microsoft disables Flash by default on Edge and IE on Windows 10 and forces users to enable Flash for each site (enabling it on adobe.com doesn't enable it on your school's site). See the following for assistance: