MinimWatch does not see MinimServer

[SNQN]

I have got a new broadband router and now MinimWatch no longer can see Minim Server. The log shows this:
"Retrying monitor subscription for server at 192.168.0.100:9791 (attempt 1)" - and so on.
MinimWatch is running on a Windows 10 PC and MinimServer on a QNAP HS-251. IP address for the QNAP is unchanged - and correct.
But I wondered about the ":9791", because in your troubleshooting guide guide you say " http://x.x.x.x:9790"