@skapoof 

The TL-WR850N is a specific edtion product, which is designed based on the ISP's requests. So it is suggested to contact ISP to get some help first.

https://service-provider.tp-link.com/wifi-router/tl-wr850n/ 

Otherwise, we can do some troubleshooting, while if we still cannot figure it out, then contact ISP will be next step.

1. Do you mean the game stops working once you setup the static IP for the PC?

2. Can you get internet with your laptop at that time? 

3. Meanwhile, please ensure that the internet IP is a public IP address.

4. Have you tried to change it back to dynamic IP and verify whether it will work? 

Good day. 

@skapoof 

Thanks for your reply.

Try to delete the virtual server entry and check whether the game works well.

The internet IP address is the WAN IP of the TL-WR850N, not the static IP you setup for the computer. 

Cause the laptop still works at that time, the troubleshooting need to be done on the specific game; it is recommended to contact the tech support of the game to verify is there any special settings need to be done.

Meanwhile, per I said before, TL-WR850N belongs to service provider dept, if there is still no solution, try to contact your ISP.

Good day.