Wow hmmm try open powershell and type in command each time:
ipconfig /flushdns
ipconfig /registerdns
ipconfig /release
ipconfig /renew
If above all still not work then I wonder what router you use?
If you know how to open router ports, you will need to add Uplay PC TCP: 443, 14000 to the list that will let Uplay ports open through router's firewall.
If it still not work, then try download VirtualBox and create VM with 32GB hard disk file to install Windows 10 and Uplay to see if it work.
If it finally work with VM then maybe your system files could be corrupted, open powershell and type in command each time:
sfc /scannow
DISM /Online /Cleanup-Image /CheckHealth
DISM /Online /Cleanup-Image /ScanHealth
DISM /Online /Cleanup-Image /RestoreHealth
If DISM repair Windows 10 will not fix it then it best to backup data, format hard disk and clean install Windows 10.