NAT test failed: Error: unexpected end of file from server

[CBell]

Hi - any advice on what to do with the above?  My mac has just upgraded to OS Catalina, and since then I've been unable to download anything via Vuze - am also running NordVPN.  I re-installed Vuze but to no avail.

When I do the NAT/ Firewall test it tells me: Testing port TCP 47017 ... Unable to test: Invalid port given, or test service failed.Another application may already be using this port.. (Error: Unexpected end of file from server).
When I do the Network Status test, all tests are successful until I get to this: 

Testing TCP port 47017 inbound
    Test failed: NAT test failed: Error: Unexpected end of file from server
    Check your port forwarding for TCP 47017
Testing UDP port 47017 inbound
    Sending outbound packet and waiting for reply probe (timeout=5000)
    Sending outbound packet and waiting for reply probe (timeout=10000)
    Sending outbound packet and waiting for reply probe (timeout=15000)
    Sending completion event
    Test failed: Inbound test failed
    Check your port forwarding for UDP 47017

Any advice?  I have no idea what I'm doing....