X-Plane error: Discover port blocked

Most likely you have something running like e.g. Hyper-V which reserved the ports that are used by X-Plane for external communication. You will need to tell it not to reserve those ports. You can check with this commands:
netsh int ipv4 show excludedportrange protocol=tcp
netsh int ipv4 show excludedportrange protocol=udp
None of the lists should include port 49707 You can change that reserved range as described here