"Trusted server" refuse to federate (icon stays yellow all the time)

Hi there.

I am currently struggling to get 2 servers to trust each other-. I am seeing this in the log my local system

{"reqId":"T436tAjEVuDycTs1aJN2","level":1,"time":"2018-02-09T20:00:18+01:00","remoteAddr":"","user":"--","app":"federation","method":"--","url":"--","message":"https:\/\/remote.host.name.com refused to ask for a shared secret.","userAgent":"--","version":"13.0.0.14"}

Ok, so https://remote.host.name.com refused to ask for a shared secret, but how could I force the server to ask for that key? The log-info is not giving me any clue? Could someone help me understand what is going wrong here?
What makes me wonder is that I can share files/data with that mentioned server, the sharing does work as expected, just this yellow icon is annoying me -even though I do not need that function, still I want to understand why & what is happening.

Cheers!

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