It is recommended that you check the IPV6 firewall
In the IPV4 network environment, in order to be connected, we usually need to open the firewall port on the router, and then do port mapping on the router to the downloading machine. IPV6 is a little different from IPV4.
Now the broadband in many areas has an IPV6 external network address by default. The IPV6 address is directly assigned to the device. For example, the router has an IPV6 address, the computer has an IPV6 address, and the NAS has an IPV6 address.
Therefore, in order to be able to be connected, check the firewall settings in 2 places:
1. Check whether the IPV6 firewall of the router is turned on. I usually turn off the firewall on the router itself.
2. Check whether the IPV6 firewall of the downloading machine is enabled.

Finally, test whether the download machine IPV6 can be connected.
1 Open the test website: https://www.port.tools/port-checker-ipv6/
2 Enter your IPv6/Host: Enter the IPV6 address of the downloader, for example: 2409:8a3c:281e:a120:211:32ff:fee9 :ebf9
3 Port to Check: Input tr's 51413
4 Click CHECK PORT

If you see the result is Success: We can see your service on, it is connected.