"Network: SymmetricNAT" problem

[SupplyDevalue]

I had the same problem.
Neither UPnP nor manual port forwarding are working when you are behind an ISP NAT.

This is why i requested a static IP from my ISP for another few bucks.
Now i have a static IP and UPnP works find without even setting a manual port forwarding in my router.
Also I tested switching off UPnP, tried manual port forwarding and it also works fine.

VPN makes things more complex, this is why i stopped using it, i just try using Tor or the exit proxy in I2P.