What kind of router do you have?
innbox v46, this one
For testing purposes put your PC into DMZ in your router UI and test again.
done, still no cigar
i find it hard to believe this kind of thing happens rarely...with all the shi.t cheap routers out there...
Try disable ipv6 maybe. Disable any network adapters except you current adapter.
I have the same problem, im also on win10...
Btw i have a very similar type of router like you, since were both croatian, you on optima ?
im optima to win 10 same problem