Not sure if this has been asked.
I assume all tests are ethernet(wired) as they need to be?
Are you using the same browsers on both Windows 7 and 10?
Are you using 2 PCs 1 with 7 and 1 with 10 on or are the windows 7 tests really old?
Which Browser do you currently use, and try other browsers?
I suspect there are settings/driver issues with your Ethernet adapter on Windows 10 compared to Windows 7 if you still have problems after reading this thread, where the guy changed his adapter to get around a similar problem, hopefully you won't have to do that.
https://answers.microsoft.com/en-us/...c-765b3a8fe4d2